from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The habitual, involuntary grinding or clenching of the teeth, usually during sleep, as from anger, tension, fear, or frustration.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The habit or practice of grinding of the teeth, as while sleeping, or due to stress or certain drugs.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. involuntarily or unconsciously clenching or grinding the teeth, typically during sleep
From New Latin brūxis, a gnashing, from Greek brūkein, to gnash.(American Heritage® Dictionary of the English Language, Fourth Edition)
Derived from Ancient Greek βρυγμός (brygmós, "grinding [teeth]") + -ism. (Wiktionary)