[JDiver]

There is a FlyerTalk Glossary of Terms commonly or even occasionally encountered on FlyerTalk. (A very few are listed below.) N.B. We try to avoid abbreviations in thread titles, because Search can not deal with three - or fewer - characters.

There is also a FlyerTalk Airport Code Lookup feature.

Unlisted aviation acronyms may be looked up here.

In addition, you may find some terms used specifically on FlyerTalk, or in the American AAdvantage Forum (or when flying AA) that may not be used commonly elsewhere; these may also vary in meaning depending on context. Some of these, as well as a number of other abbreviations, acronyms or words you may encounter on FlyerTalk, are listed below:

AA = American Airlines or AAdvantage (it’s contextual)
AAR = Airport Acceptance Rate (permitted rate of # of flights landing per hour)
AATMS = Advanced Air Traffic Management System
AC = Admirals Club lounges; sometimes, Aircraft (aircraft also a/c)
ACARS = Aircraft Communications Adressing and Reporting System
ACAS = Airborne Collision Avoidance System
ACMI = Aircraft lease with Aircraft, Crew, Maintenance and Insurance
AD = Airworthiness Directive, an FAA rule regarding specific aircraft safety issues
ADC = Air Data Computer
ADC = Code used by AA to indicate "traveling companion - remove 'stickers' from primary traveler"
ADS = Automatic Dependant Surveillance, advanced GPS based navigation system
ADT = Adult Passenger
AFS = American Flagship Service (2-class or 3-class nonstop transcon service)
Aft = rear
AFTN = Aeronautical Fixed Telecommunication Network
AHRS = Attitude and Heading Reference Systems 
AONE = oneworld explorer ticket in First
ARINC - Aeronautical Radio, Inc.
ARTC = Air Route Traffic Control Center
ASM = Available Seat Mile
ASR = Advance Seat Reservation / Airport Surveillance Radar
ATC = Air Traffic Control
ATCT = Airport Traffic Control Tower
ATCSCC = Air Traffic Control System Command Center
ATI = Anti-Trust Immunity
ATO = Airport Ticket Office
ATPCO = Airline Tariff Publishing Company)
AVOD = Audio Video On Demand (form of IFE)
BC = Business Class
BIS = "Butt In Seat" miles (EQM, gained by actual flying)
Bistro Bag = coach bag lunches retrieved from carts on boarding (obsolete)
BOB = Buy on Board; see FFS
BOGOF = Buy One Get One Free
Booking / Fare Classes = see this Wiki page
Booking Class "7" = Upgrade to next class of service from highly discounted coach 
Booking Class "8" = Upgrade to First from Business 
Booking Class "9" = Upgrade to next class of service from discounted coach 
BP = Boarding Pass
BT = Bulk Ticket
Bulkhead = "wall" separating fuselage sections
C (or D, or J) = Business Class cabin or fare class (contextual)
C01 – C17 = Child passenger and age code
CAS = Crew Alerting System (in aircraft cockpit)
CASM = Cost per Available Seat Mile
CB = Cumulonimbus clouds
Challenge, the = a way of attaining Gold or Platinum status via a "shortcut" - see the Wiki or the thread dedicated to Challenges
Cheatline = the colored line often extending down the fuselage or an aircraft
"x" Check, where "x" is A, B, C or PS = periodic maintenance - see here for AA 
CG = Center of Gravity (see Weight and Balance)
Circle Pacific = a discounted oneworld product allowing that routing
City Pairs = airports considered the same for fare construction purposes
CIR = Circle Pacific, class precedes, MPM follows, e.g. DCIR22
Co-terminals = Airports considered the same for standby and similar procedures
ConciergeKey (or CK) = Premium Service for the most valued AA customers
CONUS = Continental United States (contiguous 48 states)
COS = Class Of Service (referring to cabin service class)
CPM = Cost Per Mile
CSA = Customer Service Agent
CSR = Customer Service Representative (Corporate Social Responsibility and others as well)
CX = Cathay Pacific (secondary: cancellation)
Direct (flight) = flies with one or more stops, possibly even change of aircraft
DME = Distance Measuring Equipment
DOMUPG = Domestic Upgrade
DONE = oneworld explorer ticket in Business
DOT - (US) Department of Transportation (includes the FAA)
DSR = Passenger desiring to purchase up class of service
ECAM = Electronic Centralised Aircraft Monitor, same as EICAS, preferred Airbus version
EFIS = Electronic Flight Instrument System
EICAS = Engine Indicating and Crew Alerting System (heart of the "glass cockpit") same as ECAM
Emerald = oneworld equivalent of AAdvantage Executive Platinum
EP = Executive Platinum
EQM = Elite Qualifying Mile (a milepost used to determine status; "butt in seat" mile)
EQP = Elite Qualifying Point (ditto)
EQS = Elite Qualifying Segment
ETA = Estimated Time of Arrival
ETD = Estimated Time of Departure
ETER = Estimated Time En Route
EXP = AAdvantage Executive Platinum (chiefly on FlyerTalk; Also EP) 
EXP Line = A dedicated help desk for Executive Platinum flyers
eUPG = Electronic Upgrade
eVIP = electronic VIP international Systemwide Upgrade "certificate" or SWU
   usable for up to three segments in one direction, on most fares
F (or FC, A) = First Class cabin or fare class (A is normally discounted First)
FA = Flight Attendant
FAA = Federal Aviation Administration, part of US DOT
FAM = Federal Air Marshall
FC = First Class
FCC = Usually, London Heathrow Flight Connections Centre (on FT)
FEBO = (unofficial) Front Even, Back Odd (meal taking on many flights)
FFS = Food for Sale program in American Airlines domestic Coach 
FL = Flagship Lounge (or Flagship, contextual)
FO = First Officer (“copilot” - but see PF and PNF)
FOP = Form Of Payment
FQTR = Frequent Traveller Redemption (on BA)
FQTV = Frequent Traveller (on BA)
FS = AA's premium transcontinental Flagship Service
FT = FlyerTalk
GA = Gate Agent
Gate Lice = people with low boarding priority cluttering up the gate at boarding time
GDP = Ground Delay Program
GDS = Global Distribution System
GLD = AAdvantage Gold
GMT = (Greenwich Meridian Time) Time at Greenwich Meridian, used for some airline and military operations 
   (see UTC, Zulu Time)
Gold line = a dedicated customer service line (not separate desk) for AA Gold 
GPS = Global Positioning System (satellite based navigation system)
GS = Ground Stop
GV x = Passengers must travel together, x = number of pax
Heavy = Larger aircraft, such as 767, 777, 747, A330 - 340
HFS = Hawaiian Flagship Service
HSR = High Speed Rail
HUD = Head Up Display
IAS = Indicated Air Speed (usually in knots)
IDB = Involuntarily Denied Boarding (involuntary bump)
IFE = In Flight Entertainment
IFR = Instrument Flight Rules
IFS = International Flagship Service (to/from Europe, Asia, India, and "Deep" South America - Argentina, Brazil, Uruguay and Chile)
IFSD - In Flight Shut Down  (usually relating to an engine)
ILS = Instrument Landing System
IROPS/ IRROPS = Irregular Operations (OSO on AA - could be weather, mechanical...)
ISIC = International Student Identity Card (12 or older currently enrolled as a full-time   
  degree-seeking student at an accredited institution)
ITA = Anti-Trust Immunity
ITIC = International Teacher Identity Card (Teaching > 18 hrs / wk at an accredited institution, min 1 yr employment.
IYTC = International Youth Travel Card (age 12 - 25)
JCB = (Adult) Contract Bulk passenger
Jim Wilson - Human remains traveling in the cargo hold ("Jim Wilson Air Tray" is an air casket)
Kiosk = Self-Service Check-in Machine
Knot = unit of speed, one nautical mile per hour, kt or kn (link)
KUP = Low cost fare booking into First seat (BA F status credit!)
LAADR = Low Altitude Arrival/Departure Routing
LAHSO = Land and Hold Short Operations.
LEO = Law Enforcement Officer 
LFBU = Load Factor Based Upgrades sold at self-service check in kiosks
LFS = Latin Flagship Service (South America short-haul: Colombia, Venezuela, Ecuador, and Peru)
LIFO = Last In, First Out
LOC = Localizer (component of ILS)
LONE = oneworld explorer ticket in Coach
LRTC = (unofficial) Less Room Throughout Coach, followed MRTC
MCLA = Mexico, Caribbean and Latin America
MCO = Miscellaneous Charges Order (a kind of voucher)
MEL = Minimum Equipment List (list of equipment allowed inoperative not affecting flight safety)
METAR = MÉTéorologique Aviation Régulière (Aviation Routine Weather Report)
midcon = flight that flies mid-continent, e.g. ORD-JFK or DFW-LAX
MIL = Military Passenger
MPM = Maximum Permitted Mileage
MR = Mileage Run (trip planned primarily to earn miles, at a cheap rate)
MRTC = More Room Throughout Coach (obsolete)
MTEU = Miles Towards Elite Upgrades (counter runs from March 1 to February 28/29; elites earn 4 500 mile "sticker" upgrades every 10,000 EQ miles)
MTOW = (aircraft) Maximum Take Off Weight
MX = Mexicana (secondary: Mechanical)
NGBC = Next Generation Business Class - new angled flat seats in 763s, coming to 777s in 2008
NGSA = Next Generation Single Aisle
Nonrev = Nonrevenue (e.g. pass) flyer
Nonstop = flight that flies from origin to destination with no stops
NOTAM = NOTices to AirMen (voice or teletype information of interest to pilots)
NRP = North American Route Program
NRSA / Non-Rev = Non-Revenue Space Available flyer (e.g. NRSA Lounge at DFW)
O&D = Origin and Destination
OAG = Official Airline Guide
OH, OHB = OverHead, OH Bin
OLCI = On Line Check In
OP = Original Poster (on FlyerTalk)
Op Up = Operational Upgrade
ORC = Original Routing Credit
OSO = Off-Schedule Operations (see IRROPS)
OTS = Out Of Service
OW = One Way (trip) - OR - oneworld (Alliance) on FlyerTalk
OWE = oneworld Explorer (RTW) fare - prefixed with cabin class code, followed by # of continents - e.g. DONE4
PAWOB = Passenger Without Bags 
PDB = Pre-Departure Beverage
PED = Personal Entertainment Device
PF = Pilot Flying
PFD = Primary Flight Display or Personal Flotation Device (contextual)
PIC = Pilot In Command (SIC = Second In Command)
PIL = Passenger Item List (manifest)
PIREPS = Pilot Reports
Pitch = aircraft motion "up or down"
Plat = AAdvantage Platinum
Plat (or PLT) Lite = one who achieved Platinum status via a Challenge
Platinum line = a dedicated customer service line (not separate desk) for AA Platinum 
PLT = AAdvantage Platinum
PNF = Pilot Not Flying
PNR = Passenger Name Record, the "airline record" of your booking, usually 5 or 6 characters and airline specific
Port = Aircraft's left side as you face forward
PPR = "paper," an edit used to assure an op up doesn't automatically draw upgrade instruments, 
   usually used by the GA 
PMA = Parts Manufacturer Approval, an FAA process for aircraft parts design and manufacturing
PQ = Price Quote
PTA = Prepaid Ticket Advice 
PYOB = Print Your Own Boarding Pass
RAPCON = Radar Approach Control Facility
RASM = Revenue per Available Seat Mile
RDM = Redeemable Mile (any mile that can be redeemed for awards, etc.) 
RI = Passenger with interrupted OSO travel
RJ = Regional Jet OR Royal Jordanian (contextual)
Roger = acknowledgment used in radio communications (e.g. with control tower)
Roll = aircraft motion about the longitudinal axis
RON = Remain Over Night
ROW = Roswell Industrial Air Center, NM "the boneyard" where old aircraft go - formerly Walker Air Force Base  
RPM = Revenue Passenger Mile
RT = Round Trip
RTW = Round The World (ticket, fare or desk arranging same)
Ruby = oneworld equivalent of AAdvantage Gold
Rule 240 = Airline's domestic reaccommodation policy (AA: US, Canada, Puerto Rico, USVI) 
Rule 80 = Airline's international reaccommodation policy
RV = Revenue Passenger
RVR = Runway Visibility Reporting 
RWY = Runway
SAC = Special Assistance Coordinator 
Sapphire = oneworld equivalent of AAdvantage Platinum
SATA = Student Air Travel Association
SDR = Special Drawing Rights (international currency code XDR) 
SELCAL = Selective-Calling system (usually signal for messaging from operator to aircraft)
Short Check (bag) = Checking bag to an intermediate, not the final, destination
SIC = Seat In Coach
SIF = Selective Identification Feature (aircraft-based transponder signal)
SIGMET = SIGnificant METeorological Information
SPML = Special Meal (not available on all flights)
SPCCR = Self-Policing Community Closure Rule, used by some on this forum for proposing ignoring a thread
SRC = Senior Citizen Passenger
SSSS - Selected for Secondary Security Screening 
   (on USA BP - TSA Security will give you an extra lookover))
STC = Supplemental Type Certificate (FAA approval doc for aircraft modifications, changes or additions)
STD = Scheduled Time of Departure
STMP = Special Traffic Management Program
STPC = Stopover Paid By Carrier
Starboard = Aircraft's right side as you face forward
Sticker = 500 mile upgrade instrument (used to be actual stickers)
SUD = Boeing 747 Stretched Upper Deck (2nd or upper deck)
SVRWX = Severe Weather
SWAP = Severe Weather Avoidance Plan
SWU = Systemwide Upgrade (electronic international upgrade "certificate" on AA, often "eVIP")
TA = Ticket Agent (Travel Agent, sometimes)
TAS = True Air Speed (usually in knots)
TATL = Transatlantic; sometimes transat
TCAS = Traffic Alert and Collision Avoidance System
TCP = Total and Complete Party (Traveling together)
TPAC / Transpac = Transpacific; often transpac
TRACON = Terminal Radar Control Facility
transcon = flight crossing US coast-to-coast (Atlantic & Pacific coasts)
tstorm = thunderstorm
TTL = Ticketing Time Limit
TYP = Thank You Points
UG = UpGrade / UPG
UM or UMNR = Unaccompanied Minor (14 or under, optional 16 or 17)
US = Unserviceable / out of service
UTC = Universal Coordinated Time (see GMT, Zulu Time)
VCR = Virtual Coupon Record
VDB = Voluntary Denied Boarding (voluntary bump)
VFR = Visual Flight Rules
VIP = Systemwide Upgrade  (See eVIP; also VIPOW, obs.)
VOR = VHF (Very High Frequency) Omnidirectional Radio Range
VORTAC = (Combined) VOR and TACAN Navigational Facility
Weight and Balance = calculations affecting aircraft flying characteristics based on maximum and distributed wieght
WiFi Lice = non-lounge users who hang out near lounges to use WiFi signals
Wilco = "Will Comply," occasionally used in radio communications (e.g. with control tower)
WL = Wait List
WX = Weather
Y = Economy cabin or full fare Economy fare (contextual)
Yaw = aircraft motion "side to side"
YM = Yield Management
YMMV = Your Mileage May Vary
YRT = One year ticket
YUP / KUP = Lower priced domestic fares booking into next class of service cabin
Z following 24 hour time, or Zulu Time = see GMT, UTC

Abbreviations frequently encountered on the Internet, e.g. FWIW = For What It’s Worth, IME = In My Experience, IMO / IMHO = In My (Humble) etc.Opinion

Mainline aircraft designations and number in fleet (#616, down from 663 EOY 2007, as of Feb 2009) <link>:

AB6 = 23 (previously 34) Airbus 300-605R two-class wide body
737* = 77 Boeing 737-823 two class
757* = 124 Boeing 757-223, two class (757-121s ex-TWA gone)
757 L - 757 (18 to be in subfleet) with NGBC / Next Generation Business Class seating, 12 seats per cabin instead of usual 16
762 = 15 Boeing 767-223ER, three class transcontinental service
763* = 58 Boeing 767-323ER, two class cabins in domestic and international service (all with new near-flat J seats)
777 = 47 Boeing 777-223ER/IGW, 3-class cabins (all Flagship Suites in F, 45 with NGBC near flat seats in J)
S80 / MD80, M83 = 272 (recently 300) McDonnell Douglas MD-80 series, essentially stretched DC-9s (AKA "Mad Dog")
(revised May 2009)

* received / receiving Aviation Partners Boeing blended winglets

Airlines of the oneworld alliance

AA = American Airlines
AY = Finnair 
BA = British Airways
CX = Cathay Pacific Airways (Hong Kong, China)
IB = IBERIA (Spain)
JL = Japan Airlines, including JAL associates JALways, Japan Asia Airways, JAL Express, J-AIR and Japan Transocean Air
KA = Dragonair (China) as of 1 Nov 2007
LA = LAN airlines (Chile and Perú) now includes 4M = LAN Argentina and XL = LAN Ecuador
MA = Malév Hungarian 
MX = Mexicana (and Click Mexicana) expected to join in late 2009
RJ = Royal Jordanian
QF = QANTAS (Australia)
S7 = S7 Airlines, Russia-based, expected to join during 2010)

(N.B. Aer Lingus has departed oneworld; SN / Brussels Airlines, Swiss and Turkish never were members.)