Merriam-Webster Collegiate Dictionary - variation

 noun  Date: 14th century  1.  a. the act or process of varying ; the state or fact of being varied  b. an instance of varying  c. the extent to which or the range in which a thing varies  2. declination 6  3.  a. a change of algebraic sign between successive terms of a sequence  b. a measure of the change in data, a variable, or a function  4. the repetition of a musical theme with modifications in rhythm, tune, harmony, or key  5.  a. divergence in the structural or functional characteristics of an organism from the species or population norm or average  b. something (as an individual or group) that exhibits ~  6.  a. a solo dance in classic ballet  b. a repetition in modern ballet of a movement sequence with changes  • ~al adjective  • ~ally adverb