All round defence
Template:Short description All-around defense<ref> "fire guard" The term "all-around defense" used in a newspaper in 1944</ref> or perimeter defense<ref>https://www.marines.mil/news/publications/Documents/FM%203-21.8%20%20The%20Infantry%20Rifle%20Platoon%20and%20Squad_5.pdf Template:Webarchive "8-133. A perimeter defense allows the defending force to orient in all directions."</ref> is a type of defensive fighting position intended to give military units the ability to repel attacks from any direction.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
The positioning of the outer defensive fighting positions of a unit, is circular or triangular,<ref>https://www.marines.mil/news/publications/Documents/FM%203-21.8%20%20The%20Infantry%20Rifle%20Platoon%20and%20Squad_5.pdf Template:Webarchive "The trace of the platoon is circular or triangular rather than linear"</ref> from a bird's-eye view.
One version consists of soldiers forming a wide circle around the soldier in charge (and radioman etc.) with a spacing typically of 3–4 metres between each person (on the circle's circumference).
When a group of soldiers relocate as a part of a defensive operation, a perimeter defense can be temporarily maintained without cover.