rockabilly Syllabification: (rock·a·bil·ly)Pronunciation: /ˈräkəˌbilē/Definition of rockabilly noun a type of popular music, originating in the southeastern US in the 1950s, combining elements of rock and roll and country music. Origin: 1950s: blend of rock and roll and hillbillyrockabilly in other Oxford dictionaries Definition of rockabilly in the British & World English dictionary