Syncopation is the noun for that off-beat feel in music: the accent falls where you were not expecting it, on a weak beat or between beats, instead of on the strong beat. It can name the effect in general — 'jazz is full of syncopation' — or one particular moment, and then it has a plural: 'the syncopations in the third bar'. Musicians treat it as one of the main things that gives music life and swing; without it, a piece can sound like a march. There is also an older, quite different use that language teachers know: in the study of words, syncopation is when a sound in the middle of a word gets dropped, so 'every' comes out as 'ev'ry' and 'family' as 'fam'ly'. That sense actually came into English first, in the 1530s, and the music sense followed about sixty years later. In everyday life you will almost always meet the music one.

切分音、切分節奏（音樂）；語言學上則指「中間音省略」，例如 every 唸成 ev'ry。