"Treat" means many things.... As a noun: a special thing you give someone or do for someone knowing they will like it. "It was a real treat for the kids to ride at the front of the train. The conductor was so nice to let them ride with him." "I gave the dog some treats while I was teaching him to sit." As a verb: to do the special thing for someone's enjoyment "Let's go to the movies. I'll treat. / My treat." (I will buy the tickets and popcorn.) "He treated me to a dinner at a fancy restaurant for our anniversary." to behave in some way to someone "He treats the slaves badly." "He treats her like a queen." to use a medicine or medical procedure "They treated the patients with X to get rid of their disease. to use a chemical or other matter on something to make a change: "They treated the house with X to get rid of the bugs." There are probably some more meanings but I can't think of them.