mouth guard

noun

variants or mouthguard

ˈmau̇th-ˌgärd 

plural mouth guards or mouthguards

1

sports : a protective typically plastic device placed inside the mouth that covers the teeth and gums and often the lips and is worn especially during a contact sport (such as football, hockey, or boxing) to prevent injuries to the mouth or teeth

Clamping down on his blue mouth guard, he patrolled the area in front of the Virginia goal with the swagger and menace of a middle linebacker.

—John Walters

Although the NBA does not mandate mouthguards, many stars, including [Stephen] Curry, wear them voluntarily to prevent dental injuries.

—Aidin Vaziri

2

a

: a removable dental appliance that covers the upper or lower teeth and is worn typically at night to minimize the negative effects of various oral issues (such as bruxism)

… mouth guards are not designed to prevent clenching or grinding, but they do redistribute the forces exerted while grinding and thus help protect teeth.

—UC Berkeley Wellness Letter

called also night guard

b

: a similar device that prevents airway obstruction to treat snoring or sleep apnea

You may be a candidate for an oral appliance, fitted by a dentist experienced in treating sleep apnea. It's a mouthguard that repositions the lower jaw, tongue and uvula …

—The Toronto Star

Word History

First Known Use

1936, in the meaning defined at sense 1