Airline technology glossary: PNR, GDS, PSS, RBD, NDC and more
Search beginner-friendly airline software and industry terminology, with original IATA and ATPCO references and plain-English comparisons.
Find the term you heard in a meeting
Search plain-English definitions from schedules and inventory to ticketing, retailing and airport operations. This glossary is a practical introduction, not a replacement for the definitions in licensed IATA standards or individual airline contracts.
41 terms
AIDM
Airline Industry Data Model: IATA's industry-agreed vocabulary and data concepts for interoperability.
Ancillary
A product or service beyond the base flight, such as a paid bag or seat selection.
ATPCO
Industry supplier and publisher of airline fares, rules and retail product data used in distribution.
Authorization
Payment approval or reservation of funds under a payment provider's rules; not necessarily final capture.
Availability
Whether commercial inventory can be offered for a requested itinerary, party and selling context.
BSP
Billing and Settlement Plan: IATA framework for airline/accredited-agency sales reporting and settlement.
Cabin
Onboard class of travel, such as economy or business; different from an RBD.
Capture
Payment step instructing collection of an authorized amount; differs from later settlement.
Codeshare
An arrangement in which more than one airline markets the same operating flight under separate flight numbers.
CRS
Computer Reservation System: supports reservation creation, retrieval and changes.
DCS
Departure Control System: supports check-in, passenger processing and boarding near departure.
E-ticket
Electronic ticket recording travel entitlement and flight coupons in traditional ticketed airline workflows.
EDIFACT
Electronic Data Interchange for Administration, Commerce and Transport: traditional structured-message syntax used in travel distribution.
EMD
Electronic Miscellaneous Document: IATA-standard document used for optional services or related charges.
EMD-A
An EMD associated with an e-ticket, unlike a stand-alone EMD-S.
EMD-S
A stand-alone Electronic Miscellaneous Document, not associated for lifting with an e-ticket.
Fare basis
Fare identifier associated with a fare's commercial terms, not the same as a booking class.
Fare brand
Grouped fare attributes and benefits presented as a retail product, such as included baggage or flexibility.
Fare rule
Commercial conditions applying to the use, exchange, refund or eligibility of a fare.
GDS
Global Distribution System: platform helping travel sellers access, price, book and service travel content.
Inventory
Commercial control over capacity for sale, commonly structured by booking class and itinerary context.
Marketing carrier
Airline whose code markets a flight; it may differ from the airline operating the aircraft.
Married segment
Itinerary-linked availability control where segments may have sales conditions in combination.
NDC
New Distribution Capability: IATA Offer/Order-based XML data exchange standard for airline distribution.
O&D
Origin and Destination: the passenger's intended journey endpoints, useful in availability and revenue management.
Offer
A retail selection of products and terms made available to a customer, potentially for limited validity.
Offer Item
An identifiable component within an Offer, used to describe products or services being offered.
OMS
Order Management System: manages customer Order state and servicing in Order-centric retailing.
ONE Order
IATA initiative and standard aiming to consolidate reservation, delivery and accounting information into an integrated Order.
Operating carrier
The airline responsible for operating the flight, which can differ from the marketing carrier.
Order
Customer-centric record of purchased products or services in modern airline retailing.
OTA
Online Travel Agency: a digital travel seller that may access airline content through GDS, APIs or other integrations.
PNR
Passenger Name Record: reservation record containing itinerary and passenger-related booking details.
PSS
Passenger Service System: airline-side system family commonly covering reservations, inventory and ticketing.
RBD
Reservation Booking Designator: booking class identifier used by traditional inventory and reservations processes.
Refund
Return of money following the applicable commercial and payment workflow; distinct from simply cancelling a booking.
Revenue management
Commercial discipline using demand and inventory controls to manage saleable capacity and revenue.
Shopping
Searching and constructing candidate travel options before booking; one purchase may follow many searches.
SSIM
Standard Schedules Information Manual: IATA standard covering exchange and handling of airline schedule information.
Ticket coupon
Electronic record within a ticket corresponding to a flight entitlement and its status.
TMC
Travel Management Company: helps organisations arrange and manage business travel.
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PNR vs e-ticket vs Order
A PNR is a reservation record. An e-ticket records flight travel entitlement in traditional ticketed systems. An Order is the integrated customer-centric record intended in modern Order-based retailing.
Read the full comparison →GDS vs PSS vs DCS
A GDS helps sellers access content. A PSS manages airline-side passenger-service functions. A DCS supports airport check-in and departure processing.
Read the system comparison →Definition sources and caveats
Terms are simplified for new joiners. The IATA Airline Industry Data Model is the preferred source for industry-defined vocabulary; the IATA NDC and ONE Order programmes define their respective standards. ATPCO's original material explains how fare, rule and offer data participate in distribution.