Source : Webster's Revised Unabridged Dictionary (1913)

Enarthrosis \En`ar*thro"sis\, n. [NL., fr. Gr. ?, fr. ? jointed;
   ? in + ? joint.] (Anat.)
   A ball and socket joint, or the kind of articulation
   represented by such a joint. See {Articulation}.

Source : WordNet®

enarthrosis
     n : a freely moving joint in which a sphere on the head of one
         bone fits into a rounded cavity in the other bone [syn: {ball-and-socket
         joint}, {spheroid joint}, {cotyloid joint}, {enarthrodial
         joint}, {articulatio spheroidea}]
     [also: {enarthroses} (pl)]