Definition of “treat” - Learner’s Dictionary

treat

noun [ C ] uk us /triːt/

something special that you buy or do for someone else:

a birthday treat
As a special treat I'm taking him out for dinner.
Annie, put your money away, this is my treat (= I am paying).
→ See also Trick or treat!

(Definition of “treat noun” from the Cambridge Learner's Dictionary © Cambridge University Press)