c.1300, "negotiate, bargain, deal with," from O.Fr. traitier
(12c.), from L. tractare
"manage, handle, deal with," originally "drag about," frequentative of trahere
) "to pull, draw" (see tract
(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." The noun is first recorded late 14c., "action of discussing terms;" sense of "a treating with food and drink" (1650s) was extended by 1770 to "anything that gives pleasure." Treatment
"conduct, behavior" is recorded from c.1560; in the medical sense, it is first recorded 1744.