treat / trēt/ • v. [tr.] 1. behave toward or deal with in a certain way: she had been brutally treated he treated her with grave courtesy. ∎ (treat something as) regard something as being of a specified nature with implications for one's actions concerning it: the names are being treated as classified information. ∎ give medical care or attention to; try to heal or cure: the two were treated for cuts and bruises. ∎ apply a process or a substance to (something) to protect or preserve it or to give it particular properties: linen creases badly unless it is treated with the appropriate finish. ∎ present or discuss (a subject): the lectures show a striking variation in the level at which subjects are treated.2. (treat someone to) provide someone with (food, drink, or entertainment) at one's own expense: the old man had treated him to a drink or two. ∎ give someone (something) as a favor: he treated her to one of his smiles. ∎ (treat oneself) do or have something that gives one great pleasure: treat yourself—you can diet tomorrow.3. [intr.] negotiate terms with someone, esp. an opponent: propagandists claimed that he was treating with the enemy.• n. an event or item that is out of the ordinary and gives great pleasure: he wanted to take her to the movies as a treat. ∎ used with a possessive adjective to indicate that the person specified is paying for food, entertainment, etc., for someone else: “My treat,” he insisted, reaching for the bill.DERIVATIVES: treat·a·ble adj.treat·er n.