A joint of a finger when the fist is closed.

synonyms: knuckle joint, metacarpophalangeal joint.

Roget 244: angularity, angularness^†; aduncity^†; angle, cusp, bend; fold etc. 258; notch etc. 257; fork, bifurcation.    elbow, knee, knuckle, ankle, groin, crotch, crutch, crane, fluke, scythe, sickle, zigzag, kimbo^†, akimbo.    corner, nook, recess, niche, oriel [Arch.], coign^†.    right angle etc. (perpendicular) 216.1, 212; obliquity etc. 217; angle of 45 degrees, miter; acute angle, obtuse angle, salient angle, reentering angle, spherical angle.    angular measurement, angular elevation, angular distance, angular velocity; trigonometry, goniometry; altimetry^†; clinometer, graphometer^†, goniometer; theodolite; sextant, quadrant; dichotomy.    triangle, trigon^†, wedge; rectangle, square, lozenge, diamond; rhomb, rhombus; quadrangle, quadrilateral; parallelogram; quadrature; polygon, pentagon, hexagon, heptagon, octagon, oxygon^†, decagon.    pyramid, cone.    Platonic bodies; cube, rhomboid; tetrahedron, pentahedron, hexahedron, octahedron, dodecahedron, icosahedron, eicosahedron; prism, pyramid; parallelopiped; curb roof, gambrel roof, mansard roof.    ... show more

Dutch: knokkel
Polish: kłykieć, knykieć

Press or rub with the knuckles.

Shoot a marble while keeping one's knuckles on the ground.