knuckles
n. countable B2 Upper Intermediate US //ˈnəkəɫz// UK //nˈʌkəlz// knuck·les
n. the hard parts of your fingers where they bend. You can see them clearly when you make a fist.
n. the joints of the fingers, especially those connecting the fingers to the rest of the hand. Usually refers to the dorsal aspect of the metacarpophalangeal and interphalangeal joints.
He knocked on the door with his knuckles.
Her knuckles turned white as she gripped the steering wheel during the heavy rainstorm.
The boxer's knuckles were heavily taped to prevent injury during the high-intensity training session, ensuring the joints remained stable under repeated impact.
Usage
Almost always used in the plural unless referring to a specific single joint.