noun
brass knuckles; knuckle dusters
A weapon worn over the knuckles; wasei-eigo from 'American sack'.
wasei-eigo (Japanese-coined English), from American sack
See also: 米利堅
彼はポケットにメリケンサックを隠し持っていた。
He had a pair of brass knuckles hidden in his pocket.
Variant spelling with an interpunct; less common but still encountered.
Wasei-eigo from 'American sack', though the exact origin of the term is uncertain.