The Collaborative International Dictionary of English v.0.48:

Tendon \Ten"don\, n. [F., fr. L. tendere to stretch, extend. See
   Tend to move.] (Anat.)
   A tough insensible cord, bundle, or band of fibrous
   connective tissue uniting a muscle with some other part; a
   sinew.
   [1913 Webster]

   Tendon reflex (Physiol.), a kind of reflex act in which a
      muscle is made to contract by a blow upon its tendon. Its
      absence is generally a sign of disease. See Knee jerk,
      under Knee.
      [1913 Webster]

WordNet (r) 3.0 (2006):

tendon
    n 1: a cord or band of inelastic tissue connecting a muscle with
         its bony attachment [syn: tendon, sinew]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "tendon":
   bone, braid, brail, cable, cartilage, cord, ligament, ligation,
   ligature, line, ossicle, rope, spun yarn, string, thong, twine,
   twist, wire, yarn