a cap of loose net, as of silk or nylon, for holding the hair in place.
Origin of hair net
First recorded in 1860–65
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for hairnet
Attaching his suit to the guideline nearby, part of the rim's "hairnet," he crept out over the inside edge of the rim.
And from the edge of the rim where he clung to its hairnet, all directions were down.
British Dictionary definitions for hairnet
/ (ˈhɛəˌnɛt) /
any of several kinds of light netting worn over the hair to keep it in place
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012