tie-in . tie-in {n.} A connection; a point of meeting. John's essay on World War II provides a perfect tie-in with his earlier work on World War I. Categories: add yours world {n.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: T Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Comment on this entry