Merriam-Webster defines hair as; A slender threadlike outgrowth of the epidermis on an animal.

hair is so much more….

they are rooted inside of your skin and is the shaft of the hair is made of keratin (protein) in the form of dead skin cells.

Dartmouth.edu describes hair as pili; pilus (singular) are characteristics of mammals. Functions of the hair include protection, regulation of body temperature, a facilitation of evaporation of perspiration; hair also act as a sense organs.