sep·tet also sep·tette 
(sĕp-tĕt)
(sĕp-tĕt)n.
1. Music
a. A composition for seven voices or seven instruments.
b. A group of seven singers or seven instrumentalists.
2. A group of seven.
[German Septett, from Latin septem, seven; see sept in the Appendix of Indo-European roots.]