A composition for eight parts, usually for eight solo instruments or voices.
- Music A composition for eight voices or eight instruments.
- Music A group of eight singers or eight instrumentalists.
- A group of eight: "A train of heavy wagons rumbled north on the Winnipeg Trail, drawn by octets of oxen” ( Garrison Keillor).
- See octave.
- A set of eight valence electrons in an atom or ion, forming a stable configuration.