1. [ noun ] four people considered as a unit
Synonyms: quartette quartet

"he joined a barbershop quartet" "the foursome teed off before 9 a.m."

Related terms: gathering quadrumvirate
2. [ noun ] (mathematics) the cardinal number that is the sum of three and one
Synonyms: four 4 quaternity quatern tetrad quaternary quaternion quartet quadruplet Little_Joe IV
Related terms: digit
Similar spelling:   Foresman