chinstrap

• chin strip
• chin-strap
• chin strap

chin +‎ strap

chinstrap (plural chinstraps)

1. A strip of leather or material used to fasten a hat or helmet under the chin.
   • 1777, John Richardson, A Dictionary, Persian, Arabic, and English, page 752:

     A bridle, the chin-strap or chain.

   • 1842, “Waifs of the Waters”, in The Sporting Review:

     Such a deficit was not likely long to escape notice: the regiment was halted in the midst of a manœuvre, and, in the pause that ensued, Nosey demanded, in a grunt of thunder, how, without a chinstrap, I could expect my cap to stick upon my head.

   • 2005, Peacock, Joe, Mentally Incontinent:

     I immediately spat my mouthpiece out and unbuckled my chinstrap, yanking my helmet off of my head in a determined flash.

2. A form of beard grown under the chin.

• chinstrap penguin