What is a 3 haircut and how does it differ from other haircut styles?

A 3 haircut refers to a specific length of hair that is cut using a clipper guard size 3, which leaves the hair about 3/8 of an inch long. This length is shorter than a 2 haircut but longer than a 4 haircut. The main difference between a 3 haircut and other styles is the specific length of the hair left on the head, which can affect the overall look and style of the haircut.