Definitions: Decoy

A bit like overloading, but here there might be only a single defensive task which cannot be maintained.

Decoy: A defending piece is distracted from it's task by the decoying piece.

Averbakh Position #144
Black to move

White's Queen is tied to the defense of the mating threat at f2. 1. Ba6 using a pin by the Bishop as a decoy, Black forces the Queen away from protecting f2.