backbeat

2. A secondary or emphasized beat in a rhythmic pattern, especially beats two and four in rock and pop music.

The song's backbeat gave it a lively, driving feel.

3. A rhythmic emphasis placed on the weaker beats of a measure.

Jazz musicians often play with the backbeat to create swing.

4. A regular, repeated emphasis in any rhythmic activity, such as clapping or marching.

The crowd clapped along to the backbeat of the marching band.