Castellum

Reconstructed Limes watchtower, between Bad Nauheim and Pfaffenwiesbach, Germany.

A castellum^[1] in ancient Latin is usually either:

• a small Roman fortlet or tower,^[2] a diminutive of castrum ("military camp"), often used as a watchtower or signal station e.g. on Hadrian's Wall. It should be distinguished from a burgus, which was a later Latin term used particularly in the Germanic provinces.

• a settling or storage tank in a Roman aqueduct or it:castellum aquae.

It is the source of the English word "castle".

Ruins of the castellum divisorium in Nîmes, France, which distributed water from an aqueduct to individual water pipes.

References

1. Charlton T. Lewis, Charles Short, A Latin Dictionary
2. C. Julius Caesar, Gallic War; 2,30