Definition of Piloerection

Piloerection: Erection of the hair of the skin due to contraction of the tiny arrectores pilorum muscles that elevate the hair follicles above the rest of the skin and move the hair vertically, so the hair seems to 'stand on end.'

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=19408
Last Editorial Review: 3/19/2012