society > leisure > the arts > music > musical sound > duration of notes > [noun] > semi-breve (4)
A note having half (†in the greater prolation, one third) the length of a breve: in modern music the longest note in ordinary use. (Its figure is…
†(a) a semibreve (obsolete); (b) a pre-eminent note; also figurative.
(a) a semibreve; (b) the length of note indicated by the lower figure in the time signature of a piece.