[{"Bold_text": "noun", "List Items": ["a joint of a finger, especially one of the articulations of a metacarpal with a phalanx.", "the rounded prominence of such a joint when the finger is bent.", "a joint of meat, consisting of the parts about the carpal or tarsal joint of a quadruped.", "an or protrusion at the intersection of two members or surfaces, as in the timbers of a ship or in a roof.", "brass knuckles brass knuckles.", "a cylindrical projecting part on a hinge, through which an axis or pin passes; the joint of a hinge.", "(in a wire mesh) a bend in a wire crossing another wire.", "(on a chair arm) one of the ridges left at the front end by longitudinal flutes carved to accommodate the fingers.", "Nautical.a pronounced edge formed by a change in the form of the shell of a hull."]}, {"Bold_text": "verb (used with object)", "List Items": ["to rub or press with the knuckles.", "Marbles.to shoot (a marble) from the thumb and forefinger."]}, {"Bold_text": "verb phrase", "List Items": ["to apply oneself vigorously and earnestly; become serious:Just knuckle down for an hour or so and finish the work.Alsoknuckle under.to submit; yield.", "to apply oneself vigorously and earnestly; become serious:Just knuckle down for an hour or so and finish the work.", "Alsoknuckle under.to submit; yield."]}]