"Failure to produce milk after giving birth; an instance of this", Early 18th cent.; earliest use found in Phillips's New World of Words. From post-classical Latin agalactia lack of milk from ancient Greek ἀγαλακτία lack of milk from ἀγάλακτος + -ία. With the some forms compare -y.[agalactia etymology, agalactia origin, 英语词源]