14 C.F.R. § 260.2
As used in this part:
Air carrier means a citizen of the United States undertaking by any means, directly or indirectly, to provide air transportation.
Ancillary service means any optional service related to air travel that a covered carrier provides for a fee, beyond passenger air transportation. Such services may include, but are not limited to, transport of checked or carry-on baggage, advance seat selection, access to in-flight entertainment programs or Wi-Fi, in-flight beverages, snacks, meals, pillows and blankets, seat upgrades, and lounge access.
Automatic refund means issuing a refund to a consumer without waiting to receive an explicit refund request, when the consumer's right to a refund is undisputed because the contracted service was not provided and either the consumer rejected the alternative offered or no alternative was offered.
Break in journey means any deliberate interruption by a passenger of a journey between a point in the United States and a point in a foreign country where there is a stopover at a foreign point scheduled to exceed 24 hours. If the stopover is 24 hours or less, whether it is a break in journey depends on various factors such as whether the segment between two foreign points and the segment between a foreign point and the United States were purchased in a single transaction and as a single ticket/itinerary, whether the segment between two foreign points is operated or marketed by a carrier that has no codeshare or interline agreement with the carrier operating or marketing the segment to or from the United States, and whether the stopover at a foreign point involves the passenger picking up checked baggage, leaving the airport, and continuing the next segment after a substantial amount of time.
Business days means Monday through Friday, excluding Federal holidays in the United States.
Cancelled flight or flight cancellation means a covered flight with a specific flight number scheduled to be operated between a specific origin-destination city pair that was published in the carrier's Computer Reservation System at the time of the ticket sale but not operated by the carrier.
Cash equivalent means a form of payment that can be used like cash, including but not limited to a check, a prepaid card, funds transferred to a consumer's bank account, funds provided through digital payment methods (e.g., PayPal, Venmo), or a gift card that is widely accepted in commerce. It is not cash equivalent if consumers bear the burden for transaction, maintenance, or usage fees related to the payment.
Checked bag means a bag, special item (e.g., musical instrument or a pet), or sports equipment (e.g., golf clubs) that was provided to a covered carrier by or on behalf of a passenger for transportation in the cargo compartment of a scheduled passenger flight. A checked bag includes a gate-checked bag and a valet bag.
Class of service means seating in the same cabin class such as First, Business, Premium Economy, or Economy class, which is defined based on seat location in the aircraft and seat characteristics such as width, seat recline angles, or pitch (including the amount of legroom).
Covered carrier means an air carrier or a foreign air carrier operating to, from, or within the United States, conducting scheduled passenger service.
Covered flight means a scheduled flight operated or marketed by a covered carrier to, from, or within the United States, including itineraries with brief and incidental stopover(s) at a foreign point without a break in journey.
Foreign air carrier means a person, not a citizen of the United States, undertaking by any means, directly or indirectly, to provide foreign air transportation.
Individual with a disability has the same meaning as defined in 14 CFR 382.3 .
Merchant of record means the entity (carrier or ticket agent) responsible for processing payments by consumers for airfare or ancillary services or products (including the transport of checked bags), as shown in the consumer's financial charge statements, such as debit or credit card charge statements.
Prompt refund means refunds made within 7 business days after the earliest date the refund was requested as set forth in § 260.6(a)(2) as required by 14 CFR 374.3 for credit card purchases and within 20 calendar days after the earliest date the refund was requested as set forth in § 260.6(a)(2) for cash, check, debit card, or other forms of purchases.
Significantly delayed or changed flight means a covered flight itinerary with a delay or change made by a covered carrier where, as the result of the delay or change:
Significantly delayed checked bag means a checked bag not delivered to or picked up by the consumer or another person authorized to act on behalf of the consumer within 12 hours of the last flight segment's arrival for domestic itineraries, within 15 hours of the last flight segment's arrival for international itineraries with a non-stop flight segment between the United States and a foreign point that is 12 hours or less in duration, and within 30 hours of the last flight segment's arrival for international itineraries with a non-stop flight segment between the United States and a foreign point that is more than 12 hours in duration. The 15-hour and 30-hour standards apply to domestic segments of international itineraries.
14 C.F.R. §260.2