"to change into a different form, alter or modify the shape or character of," 1570s, from French métamorphoser (16c.), from métamorphose (n.), from Latin metamorphosis (see metamorphosis). Related: Metamorphosed. The Greek verb was metamorphoun.
1590s, "to confer the degree of doctor on," from doctor (n.). Meaning "to treat as a doctor, administer medical treatment to" is from 1712; sense of "alter, disguise for the purpose of deception, falsify" is from 1774. Related: Doctored; doctoring.
"a writing added to a will to explain, alter, add to, or revoke original terms," early 15c., from Latin codicillus "a short writing, a small writing tablet," diminutive of codex (genitive codicis) "book" (see code (n.)). Related: Codicillary.