The Oxford Thesaurus An A-Z Dictionary of Synonyms - variation n.

1) change, changing, alteration, altering, variety, varying, modification, modifying, difference, differing, diversification, diversity, diversifying, modulation, modulating, conversion, converting, permutation, permuting: We have to allow for variation in the intensity of the light. 2) variety, choice, novelty, diversity, departure (from the norm or usual) , change of pace, divergence, variegation, deviation (from the norm) : This restaurant offers considerable variation in its menu.