c. 1400, from Old French transformation and directly from Church Latin transformationem (nominative transformatio) "change of shape," noun of action from past-participle stem of transformare "change in shape, metamorphose" (see transform).
-al 1
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).