Webster's Revised Unabridged Dictionary · 1913

Talon

Talon , noun

[French, heel, spur, Late Latin talo, from Latin talus the ankle, heel.]

1.
The claw of a predaceous bird or animal, especially the claw of a bird of prey. — Bacon
2.
(Zoology) One of certain small prominences on the hind part of the face of an elephant's tooth.
3.
(Architecture) A kind of molding, concave at the bottom and convex at the top; -- usually called an ogee.

When the concave part is at the top, it is called an inverted talon.

4.
The shoulder of the bolt of a lock on which the key acts to shoot the bolt. — Knight