Source : Webster's Revised Unabridged Dictionary (1913)

Tarsi \Tar"si\, n.,
   pl. of {Tarsus}.

Tarsus \Tar"sus\, n.; pl. {Tarsi}. [NL., fr. Gr. ? the flat of
   the foot, the edge of the eyelid. Cf. 2d {Tarse}.]
   1. (Anat.)
      (a) The ankle; the bones or cartilages of the part of the
          foot between the metatarsus and the leg, consisting in
          man of seven short bones.
      (b) A plate of dense connective tissue or cartilage in the
          eyelid of man and many animals; -- called also {tarsal
          cartilage}, and {tarsal plate}.

   2. (Zo["o]l.) The foot of an insect or a crustacean. It
      usually consists of form two to five joints.

Source : WordNet®

tarsus
     n : the part of the foot of a vertebrate between the metatarsus
         and the leg; in human beings the bones of the ankle and
         heel collectively
     [also: {tarsi} (pl)]

tarsi
     See {tarsus}