What is a 4 in haircut and how does it differ from other haircut lengths?

A "4" in haircut refers to a clipper guard size that leaves hair 1/2 inch long. This length is longer than a "3" but shorter than a "5" or higher guard sizes. The difference lies in the length of the hair left on the head, with a "4" guard creating a medium-length cut compared to shorter or longer options.