Syncopation
When a performer stresses a note that is placed between beats, rather than directly on a beat, the result is called syncopation.
Syncopation is an interruption of the regular metrical accent in music caused usually when the weak beat is stressed. Syncopation is regularly used in various musical styles such as dance music. Syncopation can also occur when a performer places a strong harmony (interaction among different notes) on a weak beat.