a musical term signifying a series of notes, ascending or descending, which are to be sung to one syllable. Anciently the word had a different musical meaning. Thus Morley, in his Introduction, page 14, tells us that prolation is the measuring of semibreves by minimi, and is either greater or less. The greater prolation is when the semibreve contains three minimi. The sign of this is O or C. The less prolation is when the semibreve contains only two minimi. The sign of this is O or C.

The old musicians called the ternary measure perfect, and the binary measure imperfect.