the style in which hair has been cut
"His new haircut features a sharp fade on the sides and longer length on top."
the act of cutting the hair
"After waiting an hour for his appointment, Mark finally received his new haircut from the barber."
The act of cutting of the hair, often done professionally by a barber, hair stylist, or beautician.
"I decided to get a fresh haircut after my last appointment left me feeling like I had been run over by a lawnmower."