Definition from Wiktionary, the free dictionary
Alternative forms 
backbeat (plural backbeats)
- (music) The sharp accent on the second and fourth beats of rock music in 4/4 time.
- Just let me hear some of that rock and roll music / Any old way you choose it / It's got a back beat, you can't lose it, / Any old time you use it / It's gotta be rock and roll music / If you wanna dance with me - Chuck Berry - Rock and Roll Music