ginglymus

from WordNet (r) 3.0 (2006)

ginglymus
    n 1: a freely moving joint in which the bones are so articulated
         as to allow extensive movement in one plane [syn: {hinge
         joint}, {ginglymus}, {ginglymoid joint}]

from The Collaborative International Dictionary of English v.0.48

Ginglymus \Gin"gly*mus\, n.; pl. {Ginglymi}. [NL., fr. Gr. ? a
   hingelike joint, a ball and socket joint.] (Anat.)
   A hinge joint; an articulation, admitting of flexion and
   extension, or motion in two directions only, as the elbow and
   the ankle.
   [1913 Webster]