Numbers written on the stave at the beginning of a piece of music, and therafter when a time change occurs, indicating the number of beats in a bar (written on top) and the nature of those beats (underneath). For example denotes three crotchets in a bar, whereas warns of five quavers. The lower number is based on time value relationships with the semibreve - there are 4 crotchets in a semibreve, but 8 quavers). These signatures referred to in speech become three four time and five eight time.
