arrector pili muscle
noun
arrector pi·li muscle
| \ -ˈpī-ˌlī-
, -ˈpil-ē-
\
, -ˈpil-ē-
\
Medical Definition of arrector pili muscle
: one of the small fan-shaped smooth muscles associated with the base of each hair that contract when the body surface is chilled and erect the hairs, compress an oil gland above each muscle, and produce the appearance of goose bumps
— called also erector pili muscle, pilomotor muscle