In music, a ground bass is a bass part or bassline that repeats continually, as an ostinato, while the melody and possibly harmony over it change.
A well known classical example is the ground bass employed in Pachelbel's Canon. In popular music, many bass guitar riffs can be regarded as a modern version of the ground bass. An example is Pink Floyd's "Money" (The Dark Side of The Moon - 1973).
Ground bass