Definition of hair:
a covering for the body (or parts of it) consisting of a dense growth of threadlike structures (as on the human head); helps to prevent heat loss; "he combed his hair"; "each hair consists of layers of dead keratinized cells"
a very small distance or space; "they escaped by a hair's-breadth"; "they lost the election by a whisker"
filamentous hairlike growth on a plant; "peach fuzz"
any of the cylindrical filaments characteristically growing from the epidermis of a mammal; "there is a hair in my soup"
cloth woven from horsehair or camelhair; used for upholstery or stiffening in garments
a filamentous projection or process on an organism