treat 
(trēt)
(trēt)v. treat·ed, treat·ing, treats
v.tr.
1. To act or behave in a specified manner toward: treated me fairly.
2. To regard and handle in a certain way. Often used with as: treated the matter as a joke.
3. To deal with in writing or speech; discuss: a book that treats all aspects of health care.
4. To deal with or represent artistically in a specified manner or style: treats the subject poetically.
5.
a. To provide with food, entertainment, or gifts at one's own expense: treated her sister to the theater.
b. To give (someone or oneself) something pleasurable: treated herself to a day in the country.
6. To subject to a process, action, or change, especially to a chemical or physical process or application: treated the cloth with bleach.
7.
a. To give medical aid to (someone): treated many patients in the emergency room.
b. To give medical aid to counteract (a disease or condition): treated malaria with quinine.
v.intr.
1. To deal with a subject or topic in writing or speech. Often used with of: The essay treats of courtly love.
2. To pay for another's entertainment, food, or drink.
3. To engage in negotiations, as to reach a settlement or agree on terms: "Both sides nonetheless are quite willing to treat with [the king]" (Gregory J. Wallance).
n.
1. Something, such as one's food or entertainment, that is paid for by someone else.
2. A source of a special delight or pleasure: His trip abroad was a real treat.
[Middle English tretien, from Old French traitier, from Latin tractāre, frequentative of trahere, to draw.]
treater n.