Definition of "knuckles" []

• Plural form of knuckle. (noun)
• Brass knuckles (noun)
• Third-person singular simple present indicative form of knuckle. (verb)

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• "The sound you hear when you crack your knuckles is actually the sound of nitrogen gas bubbles bursting."
• "If you have a teenager in the troubled youth gang years, perhaps a mail order set of brass knuckles is just what Junior needs."
• "It never did heal right -- one of the knuckles is visibly sunken."