‘Variation’ in music is:

A form founded on repetition, and as such an outgrowth of a fundamental musical and rhetorical principle, in which a discrete theme is repeated several or many times with various modifications … The roots of the word variatio in the adjective varius originally referred, in non-specialized antique usage, to an impression of mixed coloration in plants and animals … Thus from the very beginning we see foreshadowed the twofold musical meanings of variation as technique and as form. (Sisman, 2003)