means A complete change of form or structure, especially the biological transformation an animal undergoes from one life stage to another, as a caterpillar becomes a butterfly.

from From Greek metamorphosis, built from meta- ("change, beyond") plus morphe ("form, shape") — literally "a changing of shape." The Romans borrowed it through Latin, and the poet Ovid pinned it to legend forever with his Metamorphoses, a sprawling catalogue of bodies turning into trees, beasts, and stars. The word arrived in English by the 1500s, first carrying the magical, mythic sense before science claimed it for caterpillars and tadpoles.