Several others chimed in that this was clearly wrong. Everyone knows it's pronounced "GRIM us".
I thought so too, but it's always best to check before making pronunciation pronouncements. Lo! It appears that "GRIM us" is an upstart. A hundred years ago, "grim ACE" was the only pronunciation for this word.
Before that, when we first borrowed the noun in the 1600s from the French grimace, we pronounced it a la francaise "gree MASS". By the time we turned the noun into a verb in the 1700s, it was being pronounced "gree MACE".
It is not uncommon for the stress in English to migrate from the second syllable to the first, leaving the vowel in the second, unstressed syllable to be reduced to a schwa. This is clearly what happened, though it is hard to say when exactly in the 20th century this came about.
One thing is for sure, when we surveyed Canadians about their pronunciation of "grimace" for the Canadian Oxford Dictionary, no one said "grim ACE", so we included only the "GRIM us" pronunciation. Other dictionaries, however, give "GRIM us" first and "grim ACE" second.
There are two theories as to the ultimate origin of "grimace":
- Middle French, alteration of grimache, of Germanic origin; akin to Old English grīma mask
- Spanish grimazo caricature, from grima fright.
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