Retrenchment is a technical term in fortification, where it is applied to a secondary work or series of works constructed in rear of existing defences to bar the further progress of the enemy who succeeds in breaching or storming these. An example was in the siege of Port Arthur in 1904.
- Spiteri, Stephen C. (2010). "Illustrated Glossary of Terms used in Military Architecture". ARX Supplement. MilitaryArchitecture.com: 641. Archived from the original on 3 June 2017. Retrieved 30 December 2015.