1. any of the cylindrical filaments characteristically growing from the epidermis of a mammal - there is a hair in my soup • Syn: hair • Derivationally related forms: pilar • Hypernyms: filament, filum • Hyponyms: ingrown hair • Part Holonyms: mammal, mammalian 2. hairlike structure especially on the surface of a cell or microorganism • Hypernyms: hair • Part Holonyms: microorganism, micro-organism