Fossa is a term used in planetary geology to describe a long, narrow, shallow depression on the body of an extraterrestrial body, such as a planet or moon. The term, which means "ditch" or "trench" in Latin, is not a geological term as such but is used in the naming of particular features, such as the Cerberus Fossae on Mars.

Fossae are believed to be the result of a number of geological processes, such as faulting, subsidence or floods of water or some other viscous liquid.

External resources

• Fossae on Mars
• Fossae on Venus
• Fossae on the Moon
• Fossae on Enceladus
• Fossae on Ganymede