Source : Webster's Revised Unabridged Dictionary (1913)

Tendril \Ten"dril\, a.
   Clasping; climbing as a tendril. [R.] --Dyer.

Tendril \Ten"dril\, n. [Shortened fr. OF. tendrillon, fr. F.
   tendre tender; hence, properly, the tender branch or spring
   of a plant: cf. F. tendrille. See {Tender}, a., and cf.
   {Tendron}.] (Bot.)
   A slender, leafless portion of a plant by which it becomes
   attached to a supporting body, after which the tendril
   usually contracts by coiling spirally.

   Note: Tendrils may represent the end of a stem, as in the
         grapevine; an axillary branch, as in the passion
         flower; stipules, as in the genus Smilax; or the end of
         a leaf, as in the pea.

Source : WordNet®

tendril
     n : slender stemlike structure by which some twining plants
         attach themselves to an object for support