Postocular

Postocular is an adjective used in biology to describe something located behind the eye. The term derives from the Latin post meaning after, and oculus meaning eye, and it is used to describe positional relationships in anatomy, zoology, paleontology, and related fields.

In anatomical descriptions, postocular refers to structures situated posterior to the orbital boundary. It is often used in the description of external morphology, such as scales or plates behind the eye in reptiles and other vertebrates, as well as to regions and sutures behind the eye in arthropods. Because anatomy varies across groups, the precise meaning can differ: some authors intend immediately behind the eye, others extend to the surrounding posterolateral area.

Examples include postocular scales in certain snakes that lie behind the eye, and postocular regions described in insect or crustacean anatomy where a mark or suture lies behind the ocular region. The term is commonly contrasted with preocular (in front of the eye) and postorbital (behind the eye socket region), though usage is not entirely uniform among taxa.

In scholarly writing, postocular is a descriptive term rather than a functional one, and it serves to locate structures in relation to the eye for identification and comparison. See also preocular and postorbital for related positional descriptors.