Treat  —v. 1 act or behave towards or deal with (a person or thing) in a certain way (treated me kindly; treat it as a joke). 2 apply a process to (treat it with acid). 3 apply medical care or attention to. 4 present or deal with (a subject) in literature or art. 5 (often foll. By to) provide with food, drink, or entertainment at one's own expense (treated us to dinner). 6 (often foll. By with) negotiate terms (with a person). 7 (often foll. By of) give a spoken or written exposition. —n. 1 event or circumstance (esp. When unexpected or unusual) that gives great pleasure. 2 meal, entertainment, etc., designed to do this. 3 (prec. By a) extremely good or well (they looked a treat; has come on a treat).  treatable adj. [latin tracto handle]