aduncous

Aduncous is an adjective used in anatomy and morphology to indicate an inward curvature, bending toward the axis or midline of a structure. The word comes from Latin aduncus, meaning “hooked inward” or “bent toward.” In biological descriptions, aduncous is applied to features that curve toward the interior rather than away from it. It is encountered in dental morphology to describe crowns or cusps with an inward tilt; in osteology to denote processes that converge toward the midline; and in descriptions of certain spines, horns, or leaf or petiole tips that curl inward.

In usage, aduncous emphasizes direction of curvature and is often used when more common descriptors such as curved, recurved, or aduncate would be insufficiently precise. Some writers substitute aduncate as an adjective form or replace it with inward-curved. The term is relatively specialized and less common in everyday anatomy; external dictionaries may note it as archaic or rare, depending on the corpus.

See also: aduncate, recurved, inward-curved.