piloerection
noun
pi·lo·erec·tion ˌpī-lō-i-ˈrek-shən 
: erection or bristling of hairs due to the involuntary contraction of small muscles at the base of hair follicles that occurs as a reflexive response of the sympathetic nervous system especially to cold, shock, or fright
Note: Piloerection may also occur as a side effect from the use of a sympathomimetic drug (such as phenylephrine) or as a symptom of opioid withdrawal.
Word History
Etymology
Latin pilus "hair" + -o- + erection
First Known Use
1930, in the meaning defined above
Medical Definition
piloerection
noun
pi·lo·erec·tion ˌpī-lō-i-ˈrek-shən
: erection or bristling of hairs due to the involuntary contraction of small muscles at the base of hair follicles that occurs as a reflexive response of the sympathetic nervous system especially to cold, shock, or fright
Note: Piloerection may also occur as a side effect from the use of a sympathomimetic drug (as phenylephrine) or as a symptom of opioid withdrawal.