Definition of "interline" [in•ter•line]

• To insert between printed or written lines. (verb-transitive)
• To fit (a garment) with an interlining. (verb-transitive)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The most restrictive measures include so-called "interline" agreements with other airlines interested in operating three key routes, quitting one of the two global alliances LAN and TAM are part of, and opening the domestic market to non-Chilean carriers, analysts say."
• "When you're dealing with tickets on multiple carriers - also called interline tickets - the odds of something going wrong increase exponentially with each airline added to your itinerary."
• "The two airlines said Wednesday they will collaborate in New York and Boston, offering their customers "interline" service that allows one-stop booking and check-in, as well as automatic bag transfers, on connecting flights to 30 destinations where they don't compete."