hair science definition

1. One of the fine strands that grow from the skin of mammals, usually providing insulation against the cold. Modified hairs sometimes serve as protective defenses, as in the quills of a porcupine or hedgehog, or as tactile organs, as in the whiskers (called vibrissae) of many nocturnal mammals. Hair filaments are a modification of the epidermis of the skin and are composed primarily of keratin. Hair also contains melanin, which determines hair color.
2. A slender growth resembling a mammalian hair, found on insects and other animals.
3. A fine, threadlike growth from the epidermis of plants. See more at trichome.

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