Foursome
Part of speech: noun
Definition: A group of four, a quartet or a game (such as golf) played by four players, especially by two teams of two.
Quartet
Part of speech: noun
Definition: A music composition in four parts, each performed by a single voice or instrument.The set of four musicians who perform a piece of music together in four parts.A group of four.
Example sentence: You hear it in your brain. Whatever makes sense. Some songs work well as quartet songs, sometimes they don't.