i vaguely recall "interstitial" being used in the pit to indicate a musical introduction, particularly one that was vamped while a scene was developing onstage in preparation for a song. perhaps wow can confirm this???

i'm not sure, regardless, if this is what you had in mind. when i read your post, i immediately thought of my Frank Sinatra christmas sheet music; he loved to add seemingly unrelated tunes and lyrics as introductions to all of the old favorites. the term used by the sheet music publisher, as indicated on the score, is simply "intro."

welcome a-Board, clearwrite... glad to have you