c.1300, "negotiate, bargain, deal with," from Old French traiter (12c.), from Latin tractare "manage, handle, deal with," originally "drag about," frequentative of trahere (past participle tractus) "to pull, draw" (see tract (n.1)). Meaning "to entertain with food and drink by way of compliment or kindness (or bribery)" is recorded from c.1500. Sense of "deal with in speech or writing" (early 14c.) led to the use in medicine (1781), "to attempt to heal or cure." Related: Treated; treating.
late 14c., "action of discussing terms," from treat (v.). Sense of "a treating with food and drink" (1650s) was extended by 1770 to "anything that gives pleasure."
v. treat·ed, treat·ing, treats
To give medical aid to someone.
To give medical aid to counteract a disease or condition.