›the number of beats in a bar of music, or the speed at which a piece of music is intended to be played: This piece is written in 4/4 time.Small children often have difficulty singing in time with the music (= at the same speed at which the music is being played).It seemed to me as if the violins were playing out of time (= at a different speed from the other instruments playing the same piece of music).To beat time is to make a regular series of sounds at the same speed as a piece of music is played.Tapping your foot will help you to keep time (= to play the music at the correct speed).Beats or lengths of musical notes