quartet

Definition (noun): the cardinal number that is the sum of three and one

Definition (noun): four performers or singers who perform together

Definition (noun): a set of four similar things considered as a unit

Definition (noun): four people considered as a unit

Example: he joined a barbershop quartet

Definition (noun): four people considered as a unit

Example: the foursome teed off before 9 a.m.

Definition (noun): a musical composition for four performers