Xenolith

A xenolith (Greek: "foreign rock") is a rock which becomes enveloped in a larger rock during the latter's development and hardening. In geology, the term xenolith is almost exclusively used to describe inclusions in igneous rock during its formation and cooling process, but a broad definition could include rock fragments which have become encased in sedimentary rock. Xenoliths are sometimes found in recovered meteorites.

To be considered a true xenolith, the included rock must be identifiably different from the rock in which it is enveloped; an included rock of similar type is called an autolith.

• Xenolith is the name of a Windows Trojan identified in January, 1998
• Xenolith is a role-playing game for the PC introduced in 2001.