1. Shortened from Old French tendrillon, from French tendre, "tender"; hence, properly, the "tender branch" or "spring of a plant".
2. 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.

Tendrils may represent the end of a stem, as in the grapevine; an axillary branch, as in the passion flower; the end of a leaf, as with the pea; or stipules (pairs of appendages at the bases of leaves).