Sestet : Another name for a sextet, a unit of quantity equal to 6. This spelling is used in poetry to describe a six-line stanza and is sometimes used in music for an ensemble of 6 instruments
Russ Rowlett (Director), How Many? A Dictionary of Units of Measurement, Center for Mathematics and Science Education University of North Carolina, USA 2005. http://www.unc.edu/~rowlett/units/dictA.html, (Unit of Meas and Covr Factors - Amer) {608}