1530s, "change of form or shape," especially by witchcraft, from Latin metamorphosis, from Greek metamorphosis "a transforming, a transformation," from metamorphoun "to transform, to be transfigured," from meta- "change" (see meta-) + morphe "form" (see Morpheus). Biological sense is from 1660s. As the title of Ovid's work, late 14c., Metamorphoseos, from Latin Metamorphoses (plural).