Source : Webster's Revised Unabridged Dictionary (1913)

Tether \Teth"er\, v. t. [imp. & p. p. {Tethered}; p. pr. & vb.
   n. {Tethering}.]
   To confine, as an animal, with a long rope or chain, as for
   feeding within certain limits.

         And by a slender cord was tethered to a stone.
                                                  --Wordsworth.

Source : WordNet®

tethered
     adj : confined or restricted with or as if with a rope or chain