3DAAP Three-dimensional airspace analysis program
3PL Third Party Logistics
3PLP Third Party Logistics Providers
4PL Fourth Party Logistics
AAAE American Association of Airport Executives
AC Advisory Circular
ACAS Automated card access system
ACC (1) Area Control Centre (air)
ACC (2) Adaptive Cruise Control (road)
ACCC Airport command control center
ACFT Aircraft
ACI Airports Council International
ACM Airport certification manual
ACO Aircraft certification office
ACTS Advanced Communication Technologies and Services
AD Airport design
ADA Americans with Disabilities Act
ADAS (1) Action Data System. System in use in some European Coast Guards
ADAS (2) Advanced driver assistance system (road)
ADF Automatic direction finder
ADG Airplane design group
ADGS Aircraft docking guidance system
ADO Airport District Office (FAA)
ADRT Alternate departure route
ADS-B Automatic Dependent Surveillance-Broadcast (air)
AEP Airport emergency plan
AF Airway Facilities (FAA)
AFIS Automated flight inspection system
AFS Airways facilities sector
AFSFO Airways facilities sector field office
AFSO Airways facilities sector office
AFSS Automated flight service station
AGL Above ground level
AGTS Automated ground transportation system
AIC Airport information system
AILS Automatic instrument landing system
AIMS Airport integrated mapping system
AIP Airport Improvement Program
AIS (1) Aeronautical Information Services (air)
AIS (2) Automatic Identification System (waterborne, road)
AIS Automated information security
ALP Airport layout plan
ALS Approach lighting system
ALSF-1 Standard 2400’ high-intensity approachlighting system with sequenced flashers (Category Iconfiguration)
ALSF-2 Standard 2400’ high-intensity approachlighting system with sequenced flashers (Category IIconfiguration)
ALT Altitude
AMC Airspace Management Cell (air)
AMF Air mail facility
AMGR Airport manager
ANG Army National Guard
ANT Antenna
AOA At or above; aircraft operational area
AOB At or below
AOC Airline Operations Centre (air)
AOR Airport operational readiness
AP Airports Division (FAA)
APL Airport lights
APPM Accident prevention program manager
APS Advanced Planning and Scheduling: a function within -> SCM
ARAC Army radar approach control facility
ARC Archive System of CFMU (air)
ARC Airport reference code
ARCC Air Rescue Co-ordination Centre (air)
ARFF Aircraft rescue and firefighting
ARP Airport reference point
ARPA Automatic Radar Plotting Aid
ARPT Airport
ARSA Airport radar service area
ARSC Air Rescue Sub Centre, respons. for aeronautical accidents and incidents (air)
ARSR Air route surveillance radar
ARTCC Air Route Traffic Control Center
ARTEMIS Project management software
ARTS Automated radar terminal system
ASAP As soon as possible
ASDA Accelerate-stop distance available 
ASDE Airport surface detection equipment
ASL Above sea level
ASM Airspace Management (air)
ASOS Automatic surface observing system
ASP Airport security plan; airspace
ASPH Asphalt
ASR Airport surveillance radar
ASV Annual service volume
AT Air Traffic Division (FAA)
ATA (1) Actual Time of Arrival
ATA (2) Air Transport Association
ATA Air Transport Association of America
ATBA Area to be avoided (waterborne)
ATC Air Traffic Control (air)
ATC Air traffic control
ATCF Air traffic control facility
ATCT Airport Traffic Control Tower
ATD Actual Time of Departure
ATFM Air Traffic Flow Management (air)
ATIS Airport traffic information service
ATM Air Traffic Management (air)
ATM Air traffic manager
ATO Airline ticket office
ATOG Allowable takeoff gross weight
ATS Air Traffic Services (air)
AVGAS Aviation gasoline
AVI Automatic vehicle identification
AVMS Automatic Vessel Monitoring System
AVN Aviation standards national field office
AWOS Automated weather observing system
AZ Azimuth
BCN Beacon
BIDS Baggage information display system
BMS Basic meteorological services
BRITE Bright radar indicator tower equipment
BRL Building restriction line
BUEC Backup emergency communications
BUL Bulletin
C Circling (approach and landing charts)
CAA Civil Aviation Authorities (air)
CAACE Comité des Associations d'Armateurs de la Communauté Européenne
CAD Computer aided dispatch
CADD Computed aided design and drafting
CAFM Computer aided facility management
CAP Civil Air Patrol
CAS Collision avoidance system; calibrated airspeed
CASFO Civil aviation security field office
CAT I, II, III Category of ILS approach
CBI Computer based instructions
CCR Commission Centrale du Rhin (waterborne). Active in creating standards for waterborne traffic and transport
CCTV Closed-Circuit Television
CCTV Closed-circuit television
CDM Collaborative Decision Making (air)
CEC Certificate of Competence
CEN CEN - The European Committee for Standardization
CENELEC European Committee for Electrotechnical Standardization
CEPT European Conference of Postal and Telecommunications Adminstrations
CES Coast Earth Station. An Inmarsat communication station on the earth surface
CFM Confirm
CFMU Central Flow Management Unit, part of -> EUROCONTROL (air)
CFW Center field wind
CHIRP Confidential Hazardous Incident Reporting Programme
CIFP Cancel IFR flight plan
CIFR Cancel IFR clearance previously given
CIP Capital improvement program
CLF Cableless Linking of intersections for co-ordinated traffic flow (road)
CMMS Computerized maintenance management system
CNS Communications, Navigation and Surveillance (air)
CNTRLN Centerline
COLREGS Convention on the International Regulations for Preventing Collisions at Sea
CPA Closest Point of Approach (waterborne)
CPTY Capacity
CRS (1) Coast Radio Station (waterborne)
CRS (2) Computer Reservation System
CSL-DB Common Source Logistics Database (inland waterways)
CSO Company Security Officer
CSS Coastal Surface Search. A vessel co-ordinating surface -> SAR (waterborne)
CTGY Category
CTLR Controller
CTLZ Control zone
C-TPAT Customs - Trade Partnership Against Terrorism (US Customs)
CTS Cordless Telephone System
CUTE Common use terminal equipment
CWA Coast Watching Unit
CWY Clearway
DA Departure approved
DAB Digital Audio Broadcast (road) used to transmit traffic information to vehicles
DB Decibel
DBA A-weighted decibels; database administrator
DBE Disadvantaged business enterprise
DBMS Database Management System
DBMS Database management system
D-BRITE Digital brite radar indicator
DCA Digital Channel Allocation
DCPA Distance at Closest Point of Approach
DCRZ Descend to and cruise
DCS Digital Channel Selection
DD Deep draught
DDFTS Demand-Driven Freight Transport Systems
DECT Digital Enhanced Cordless Telephone
DEMARC Demarcation point
DETRESFA Distress Phase. Vessel / person in danger, requires immediate assistance
DF Direction Finding
DGNSS Differential Global Navigation Satellite System
DGPS Differential Global Positioning System
DH Decision height
DLC Delayed clearance
DME Distance measuring equipment
DMEG DME collocated with glide slope
DMEL DME collocated with localizer
DMEV DME collocated with VOR
DMS (1) Dynamic Message Signs cf. -> VMS (road) DRIP
DMS (2) Destination Management System
DOT Department of Transportation
DRIP Dynamic Route Information Panels (road) -> VMS -> DMS
DRIS Dynamic Route Information System (road) -> VMS -> DMS
DRIVE Dedicated Road Infrastructure for Vehicle safety in Europe (road)
DSC Digital Selective Calling
DSRC Dedicated Short Range Communications, esp. for tolling systems (road)
DSRR Digital Short Range Radio
DTF Digital Terrain File
EA Environmental assessment
EAD European Aeronautical Database (air)
EAN European Article Numbering, developed by EAN International, European counterpart of -> UCC
EARTS En route automated radar tracking system
EAS Equivalent airspeed; essential air service
EAT Expected approach time
EATCHIP European Air Traffic Control Harmonisation and Integration Programme (air)
ECAC European Civil Aviation Conference (air)
ECDIS Electronic Chart Displaying Information Systems (waterborne)
EDGE Enhanced Datarates for Global Evolution
EDI Electronic Data Interchange
EDI Electronic data interchange
EDIFACT Guidelines for the definition of electronic messages regarding EDI and scenarios of transactions between two parties
EDMS Electronic document/drawing management system
EDS Environmental Data Service
EEM External Error Mode
EFAS En Route Flight Advisory Service
EFC Electronic Fee Collection (road)
EFF Effective
EFR Expect further routing
EIA European Intermodal Association
EIS Environmental impact study
EL Elevation
ELAT/ELONG Estimated latitude/longitude
EMC Electro-magnetic compatibility
EMI Electro-magnetic interference
EMLPP Enhanced MultiLevel Precedence and Preemption - GSM-R service for prioritised calls (e.g. in case of emergency)
EMRS European Maritime Reporting System (waterborne)
EMS Environmental Management System
ENC Electronic Navigation Chart (waterborne)
ENRT En route
ENV Environmental Database of -> CFMU (air)
EP Enplaned passenger
EPA Environmental Protection Agency
EPC Electronic Product Code to be used on -> RFID tags
ERAD En route radar (broad band)
ERC European Radio-communication Committee. This is a part of ->CEPT
ERP Enterprise Resource Planning
ERSP En route spacing program
ERTMS European Rail Traffic Management System (rail)
ESN European Short Sea Network
ESU Environmental service unit
ESV Extended air service volume
ETA Expected Time of Arrival
ETA/D Estimated time of arrival/departure
ETCS European Train Control System (rail)
ETD Expected Time of Departure
ETG Enhanced target indicator
ETSI European Telecommunications Standards Institute
ETV Emergency Towing Vessel (waterborne)
EVI Electronic Vehicle Identification (road)
EXEC-1:  President on board civil aircraft
FA Final approach
FAA Federal Aviation Administration
FAR Fatal Accident Rate
FAR Federal Aviation Regulations
FARADEX Functional Architecture Reference for ATM systems and Data Exchange (air)
FBI Federal Bureau of Investigation
FBO Fixed-base operator
FCC Federal Communications Commission
FCD Floating Car Data
FCST Forecast
FDAD Full digital alphanumeric display
FDIO Flight data input/output
FEXHA Fuel supply exhausted
FGDC Federal Geospatial Data Committee
FIDS Flight information display system
FIFO Flight inspection field office
FIS Fairway Information System (waterborne)
FIS Federal Inspection Station(customs/immigration)
FL Flight level
FLP Facility layout plan
FMS Facility management standard/system
FP Flight plan
FPL Flight Plan (air)
FRH Fly runway heading
FS Flight standards (FAA)
FSA Formal Safety Assessment
FSDO Flight Standards District Office
FSNFO Flight Standards National Field Office
FSO Fuel services operator
FSS Flight service station
FTMS (1) Freight Transport Management System
FTMS (2) Freight Transport Monitoring System
FY Fiscal year
GA General aviation
GADO General Aviation District Office
GB Gigabytes
GC Ground control
GEO Geosynchronous Earth Orbit
GIS Geographical Information System
GLONASS Global Navigation Satellite System. A Soviet space-based navigation system similar to GPS
GMDSS Global Maritime Distress and Safety System (waterborne)
GMS Gate management system
GMT Greenwich Mean Time
GNSS Global Navigation Satellite System (air)
GOES Geostationary orbiting environmental satellite
GOVT Government
GP Glide path
GPRS General Packet Radio Service
GPS Global Positioning System
GPS Global positioning system
GS Glide slope
GSM Global System for Mobile communications
GSM-R Global System for Mobile communications - Railway
GT Gross Tonnage
GUI Graphical User Interface
GV Ground visibility
GVGI Generic visual slope indicator
GWT Gross weight
HAA Height above airport
HAPI Holding as previously instructed
HAT Height above touchdown
HAZMAT Hazardous Material
HAZOP Hazard and Operability Study
HCC Harmonised Customs Code
HDTA High density traffic airport
HEL Helicopter
HEL-H Heavy Helicopter
HELI Heliport
HEL-L Light helicopter
HEL-M Medium Helicopter
HEP Human Error Probability
HF High Frequency
HGV Heavy Goods Vehicles (road)
HIRL High intensity runway lights
HMCG Her Majesty's Coast Guard
HNGR Hangar
HOP Helicopter operations; hand-off point
HRA Human Reliability Analysis
HSC High Speed Craft
HSCD High Speed Circuit Switched Data
HTML Hyper Text Mark-Up Language
HTTP Hyper Text Transfer Protocol
HUB Area designation based on level of enplanedpassengers
HVAC Heating, ventilating and air conditioning
HWY Highway
Hz Hertz (frequency – electrical)
IAF Initial approach fix
IALA International Authority of Lighthouse Associations (waterborne)
IAPA Instrument approach procedure automation
IATA International Air Transport Association (air)
ICAO International Civil Aviation Organisation (air) Promotes understanding and security through cooperative aviation regulation.
ICAO International Civil Aviation Organization
ICCS Integrated Coastguard Communication System (waterborne)
ICD Interface control document
ICSS Integrated communications switching system
ICT Information and Communication Technology
ID Identification
IEC International Electro-technical Commission.
IEEE Institute of Electrical and Electronics Engineers.
IFILS Instrument landing system
IFPS Integrated Initial Flight Plan Processing System of -> CFMU (air)
IFPU Initial Flight Plan Processing Unit (air)
IFR Instrument flight rules
IFTDGN International Forwarding and Transport Dangerous Goods Notification message
IHO International Hydrographic Organisation
ILO International Labour Organisation
ILS Instrument landing system
IM Inner marker
IMC Instrument meteorological conditions
IMDG International Maritime Dangerous Goods Code
IMO International Maritime Organisation
IMO FAL Form 1 General declaration
IMO FAL Form 2 Cargo Declaration (commonly replaced by standardised cargo manifests)
IMO FAL Form 3 Ship's Store Declaration
IMO FAL Form 4 Crew's Effects declaration
IMO FAL Form 5 Crew List
IMO FAL Form 6 Passenger List (ships carrying max. 12 passengers)
IMO FAL forms Ship declaration forms by the -> IMO
INDRIS Inland Navigation Demonstrator of River Information Services (waterborne)
INM Integrated noise model
INST Instrument
IOS Initial operating capability
IP Internet Protocol
IR Ice on runway
IRPS Inter-urban Road pricing schemes (road)
ISDN Integrated Services Digital Network
ISI Inter System Interface
ISM International Safety Management
ISO International Organization for Standardisation
ISP Internet Service Provider
ISPS Code International Ship and Port Facility Security Code
ITE Integrated Transport Environment
ITNRNT Itinerant
ITU International Telecommunication Union
JAL Jet approach landing charts
JCTN Junction
JIT Just In Time
JTSTR Jet stream
KAREN Keystone Architecture Required for European Networks (road)
khz Kilohertz
KM Kilometers
KPI Key Performance Indicator
KT Knots; knowledge management
kW Kilowatt
LAN Local area network
LAT Latitude
LCOM Compass locator at ILS middle marker
LDA Localizer type directional aid; landing distanceavailable
LDIN Lead in lighting system
LDN Day-night average noise level
LED Liquid electronic Display
LIRL Low intensity runway edge lights
LIRS Low-impact resistant supports
LLWAS Low level wind shear alert system
LMS Lease management system
LOA Letter of agreement
LOC Localizer
LOI Letter of intent
LONG Longitude
LORAN-C A low frequency hyperbolic radio navigation system
LRG Long range aircraft
LRM Logistics Resource Management
LST Local standard time
LTF Local training flight
MACH Speed ratio to speed of sound
MAEW Men and equipment working
MAIB Marine Accident Investigation Branch (of the UK Government)
MALS Medium intensity approach lighting system
MALSF Medium intensity approach lighting system withsequenced flashers
MALSR Medium intensity approach lighting system withrunway alignment indicator lights
MAP Missed approach point; million annualpassengers
MARPOL Marine Pollution
MARPT Municipal airport
MB Marker beacon; megabytes
MBE Minority business enterprise
MCA Maritime and Coastguard Agency
MCA Minimum crossing altitude
MCC Mission Control Centre, ground station of COSPAS-SARSAT satellite system
MCC Maintenance control center
MDA Minimum descent altitude
MEA Minimum enroute altitude
MEO Medium Earth Orbit
MF Medium Frequency
MFL Maintain flight level
MFS Master flight schedule
MGR Manager
MHz Megahertz
MIRL Medium intensity runway edge lights
MIS Management information systems
MIT Miles in trail
MLS Microwave landing system
MM Middle marker
MMS Maintenance management system
MOA Military operations area
Mode-S Discrete addressable secondary radar system withdata link
MOU Memorandum of Understanding
MRCC Maritime Rescue and Co-ordination Centre. A RCC responsible for maritime search and rescue incidents
MRG Medium Range Aircraft (air)
MRSC Maritime Rescue subcentre. responsible for maritime -> SAR incidents
MSC Mobile Switching Centre. Connects a wireless and public telephone network.
MSC Marine Safety Committee
MSL Mean sea level
MT Mobile Terminal
MTC Motorway Traffic Control Centre
MTR Military training route
MUFIDS Multi-user flight information display system
MVSP Maintain visual separation
NAD North American datum
NAF Naval air facility
NAS National Airspace System; Naval Air Station
NASA National Aeronautics and Space Administration
NASP National Airport System Plan
NATCAS Navigation, air traffic control, and collisionavoidance system
NATS Noise Abatement Test System
NAV Sub-committee on Safety of Navigation (waterborne)
NAV Navigation
NAVAID Navigational aid
NAVD North American vertical datum
NCDC National Climatic Data Center
NDB/DME NDB collocated with a DME
NDB Non-directional beacon
NFDC National flight data center
NGS National geodetic survey
NIAC NAS Information Architecture Committee (FAA)
NM Nautical mile
NMS Noise management system
NOAA National Oceanic and AtmosphericAdministration
NOMS Noise monitoring system
NORAD North American Air Defense Command
NORST No restrictions
NOS National Oceanic Survey
NOTAM Notice to Airmen
NP Non-precision (markings)
NPI Non-precision instrument
NPIAS National Plan of Integrated Airport Systems
NPRM Notice of proposed rulemaking
NRA Non-rule action
NTIS National Technical Information Service
NTP Notice to proceed
NTSB National Transportation Safety Board
NWS National Weather Service
O&D Origin & destination
OARTS Oceanic Air Route Tracking System
OBC On Board Computer
OBU On Board Unit (road) typically for toll collection
OCIP Owner-controlled insurance program
ODALS Omnidirectional approach lighting system
ODBC Open Database Connectivity, Microsoft-owned protocol for database access
OEM Original Equipment Manufacturer
OFA Object-free area
OFS Official Shipping Number
OFZ Object-free zone
OGC Open Geospatial Consortium, Inc.
OM Outer marker
OMS Obstruction management system
OMT Object Modelling Tool
OPRC Oil Pollution preparedness, Response and Co-operation (waterborne)
OPS Operations
ORL Overrun lights
OSC On scene Commander (rescue)
OSI Open System Interconnection Standards
OSS One Stop Shop
OVRN Overrun
P Precision (markings)
PA Precision approach; pressure altitude
PABX Private Automatic Branche Xchange
PAJA Parachute jumping activities
PAPI Precision approach path indicator
PAR Precision approach radar
PAX Precision approach radar
PBX Private Branche eXchange
PCA Preconditioned air
PCI Pavement condition index
PCPN Precipitation
PDA Personal Digital Assistant
PDC Pre-departure clearance
PDP Position Data Provider
PFSO Port Facility Security Officer
PIANC Permanent International of Association Navigation Congresses, now International Navigation Association
PIR Precision instrument runway
PLB Passenger loading bridge
PLMN Private Land Mobile Network
PML Product Markup Language. A new XML dialect used in the context of -> ePC
PMS Pavement management system
POA Privately owned aircraft
PPP Private-Public Partnership
PRA Probabilistic Risk Analysis
PRIM Primary
PRIRA Primary radar
PROP Propeller
PS Passenger service
PSGR Passenger
PSTN Public Switched Telephony Network
PWC Potable water cabinet
PWI Proximity warning indicator
QFLOW Quota flow procedures
QUAD Quadrant
R/W Runway
RACON Radar responder beacon
RAGF Remote air-ground facility
RAID Risk Analysis for ITS Deployment
RAIL Runway alignment indicator lights
RATCF Radar air traffic control facility (USN)
RCAG Remote communications air-ground facility
RCC Rescue Co-ordination Centre
RCF Remote communications facility
RCL Radio communications link
RCLM Runway centerline marking
RCLS Runway centerline light system
RCO Route Charging Office (air)
RCO Remote communications outlet
RCT Ramp control tower
RDS Radio Data System -> RDS-TMC
RDS-TMC Radio Data System - Traffic Message Channel, FM Multiplex one-way communication used to transmit traffic information to road vehicles
REG Regulation
REIL Runway end identifier lights
RF Radio Frequency
RF Radio frequency
RFID Radio Frequency Identification. Using active (powered) transponders or passive tags
RFP Request for proposal
RFQ Request for qualifications
RIS River Information Services
RNAV Area navigation
ROFA Runway object-free area
ROTG Rotating
ROW Right of way
RPL Repetitive Flight Plan Processing System of -> CFMU (air)
RPM Revenue passenger miles
RPZ Runway protection zone
RRL Runway remaining lights
RRP Runway reference point
RSA Runway safety area
RSO RRegistered Security Organization
RTA Required Time of Arrival
RTE Route
RTIS Regional Traffic Information Service
RU Rescue Unit
RV Rescue Vessel. Long range seagoing craft (waterborne)
RV Radar vector
RVR Runway visual range
SA System Architecture
SAGIS State airport GIS
SALS Short approach lighting system
SAR Search and Rescue (air, sea)
SATIN System Architecture and Traffic control Integration
SCADA Supervisory Control And Data Acquisition. See for example, Dayton & Knight Ltf
SCC Ship Control Centre (waterborne)
SCIP Surveillance communications interfaceprocessor
SCM Supply Chain Management
SCOOT Split, Cycle and Offset Optimisation Technique, used in -> UTC (road)
SDS Spatial data standard
SES Ship Earth Station. An INMARSAT ship borne communication terminal which could be installed in a -> RCC (waterborne)
SFC Surface
SFL Sequence flashing lights
SIA Standard instrument approach
SID Standard instrument departure
SIM Subscriber Identification Module
SL Sea level
SLP Slope
SM Statute mile
SMGCS Surface movement guidance and control system
SMNV Standard Marine Navigation Vocubulary (waterborne)
SMPC Standard Marine Communication Phrases (waterborne)
SMS (1) Short Message Service
SMS (2) Safety Management System
SMSA Standard metropolitan statistical area
SMTP Simple Mail Transfer Protocol
SOLAS International Convention for the safety of Life at Sea
SONET Synchronous optical network
SOP Standard operating procedure
SRG Short Range Aircraft (air)
SRR Search and Rescue Region
SSALF Simplified short approach lighting system withsequenced flashers
SSALR Simplified short approach lighting system withrunway alignment indicator lights
SSALS Simplified short approach lighting system
SSO Ship Security Officer
SSR Secondary surveillance radar
SSS Short Sea Shipping (waterborne)
STAR Standard terminal arrival route
STCW International Convention on Standards of training, Certification and Watchkeeping for seafarers (waterborne)
STI Strategic Traffic Information (waterborne)
STIS Shipping Transport and Information Services (waterborne)
STOL Short takeoff and landing
SWY Stopway
SYS System
TAC Terminal area chart
TACAN Tactical air navigational aid
TACT Tactical Database of -> CFMU (air)
TAD ATC tower, approach and departure controlfacility
TARDIS Traffic and Roads- DRIVE Integrated Systems (road)
TASR Terminal area surveillance radar
TBD To be determined
TBS Transmission-Based Signalling (rail)
TCA Terminal control area
TCH Threshold crossing height
TCMS Transport Chain Management System
TCP/IP Transmission Control Protocol / Internet Protocol
TDMA Time Division Multiple Access
TDWR Terminal Doppler weather radar
TDZ Touchdown zone
TDZL Touchdown zone light (system)
TELCO Telecommunications
TEN Trans-European network
TERPS Terminal instrument procedures
TETRA Terrestrial Trunked RAdio
TFC Traffic
TGL Touch and go landing
TH  Threshold
TIC Traffic Information Centre
TICS Transport Information and Control Systems
TIPS Terminal information processing system
TKOF Takeoff
TL Taxilane
TMC Traffic Message Channel; road-side sensors transmit traffic information via -> TIC and -> RDS-TMC to vehicles
TMC Traffic management coordinator
TMS Traffic Management System
TOA Takeoff run available
TODA Takeoff distance available
TOG Takeoff gross weight
TOPS Total Operations Processing System (rail). Monitors, records and reports details of train activity, train formation and schedule performance on the network
TPEG Transport Protocol Experts Group. An emerging standard -> TTI multimedia service (alternative to -> TMC) supposed to cover all transport modes
TR VFR low altitude training route
TRACON Terminal Radar Approach Control Facility
TRAD Terminal radar
TRSA Terminal radar service area
TSA Taxiway safety area
TSI Technical Specifications for Interoperability (rail)
TSS Traffic Separation Scheme (waterborne)
TTI (1) Traffic and Traveller Information
TTI (2) Tactical Traffic Image (waterborne)
TVOR Very high frequency omnirange located on anairport
TW  Taxiway
UAIS Universal -> AIS (waterborne)
UCC Uniform Code Council, responsible for -> UPC. American counterpart of -> EAN International
UDDI Universal Description, Discovery and Integration
UHF Ultra high frequency
UIC Union Internationale des Chemins de Fer (rail)
ULR Ultra Long Range Aircraft (air)
UML Unified Modelling Language
UMTS Universal Mobile Telecommunication System
UNATNDD Unattended
UNECE United Nations Economic Commission for Europe
UNKN Unknown
UPC Uniform Part Code, the American Barcode standard developed by -> UCC
UPS Uninterruptible power supply
URI Uniform Resource Identifier
URL Uniform Resource Locator
USAPHIS  U.S. Animal and Plant Health InspectionService
USCS  U.S. Customs Service
USGS U.S. Geological Survey
USI&NS U.S. Immigration and NaturalizationService
USPHS U.S. Public Health Service
USPS U.S. Postal Service
UTC (1) Universal Time Code (GMT)
UTC (2) Urban Traffic Control (road)
V Visual (markings)
VA Victor Airways
VAPS V/STOL approach system
VASI Visual approach slope indicator
VBS Voice Broadcast Service - a GSM application developed within -> GSM-R
VCTR Visual approach slope indicatorector
VDL M2 VHF Digital Link Mode 2 (air)
VDR Voyage Data Recorder (waterborne)
VFM Vehicle Fleet Management (rail)
VFR Visual approach slope indicatorector
VGCS Voice Group Call Service - a GSM application developed within -> GSM-R
VGPI Visual approach slope indicatorector
VHF Very High Frequency (30-300MHz)
VHF Visual approach slope indicatorectorery high frequency
VLR Very Long Range Aircraft (air)
VMC Visual approach slope indicatorectorery high frequency
VMS Variable Message Signs cf. -> DMS (road)
VOR/DME VOR and DME (colocated)
VOR VOR and DME (colocated)ery high frequency omni range
VORTAC VOR and TACAN (colocated)
VOT very high frequency omnidirectional range test
VR  VFR military training routes
VSTOL Vertical/short takeoff and landing
VTM Vessel Traffic Management (waterborne)
VTMIS Vessel Traffic Management and Information Services
VTS Vessel Traffic Services
WAC World aeronautical chart
WAN  Wide area network
WBE  Woman-owned business enterprise
WCO World Customs Organization
WFMC Work Flow Management Coalition
WICA While in control area
WICZ While in control zone
WND Wind
WR Wet runway
WSDL Web Services Description Language
WW Severe weather forecast
WWNWS World-wide Navigational Warning Service (waterborne)
WWRNS World Wide Radionavigation System (waterborne)
WX Weather
XMTR Transmitter
Z Greenwich Mean Time