NCIt definition : A tube-like invagination of the epidermis from which the hair shaft develops and into
which the sebaceous glands open; the follicle is lined by a cellular inner and outer
root sheath of epidermal origin and is invested with a fibrous sheath derived from
the dermis.;
Alternative definition : NCI-GLOSS: A shaft or opening on the surface of the skin through which hair grows.; CDISC: A tube-like invagination of the epidermis from which the hair shaft develops
and into which the sebaceous glands open; the follicle is lined by a cellular inner
and outer root sheath of epidermal origin and is invested with a fibrous sheath derived
from the dermis. (NCI);