leitmotif \LYT-moh-teef\, noun:
1. In music drama, a marked melodic phrase or short passage which always accompanies the reappearance of a certain person, situation, abstract idea, or allusion in the course of the play; a sort of musical label.
2. A dominant and recurring theme.
One theme had recurred so frequently in these conversations that it had become the leitmotif of the trip.
-- Jack F. Matlock Jr., Autopsy on an Empire