What is Buy ?
Buy is (verb) to get something by paying money I bought a newspaper on my way to the station. She’s buying a flat. She bought herself a pair of ski boots. What did you buy your mother for her birthday? (NOTE: buying bought ) (noun) something bought. Synonym purchase a good buy something which you have bought which is worth the money spent That camera you bought was a very good buy.
source: Easier English, Student Dictionary Upper Intermediate Level