1. the joints of the fingers, especially where they join the hand
Usage: plural form of knuckle

Examples

• He cracked his knuckles before typing.
• She scraped her knuckles on the rough wall.
• The boxer’s knuckles were bruised after the fight.
• Cold weather made her knuckles stiff and sore.
• He rapped his knuckles on the wooden door.
• The child’s knuckles were dirty from playing outside.