Yours, Etc.: Origins and Uses of 8 Sign-Offs
mid-15c., "transformation," from Old French deformation and directly from Latin deformationem (nominative deformatio), noun of action from past participle stem of deformare (see deform).
deformation de·for·ma·tion (dē'fôr-mā'shən, děf'ər-)n.
An alteration in shape or structure of a previously normally formed part.