Vallum

A vallum (plural: valla) is a term derived from Latin that refers to a defensive barrier, most often an earthen rampart or wall. The term can encompass a variety of defensive structures depending on the context.

Roman Context:

In Roman military usage, a vallum most frequently refers to the earthworks that constituted a Roman military fortification, especially a temporary or semi-permanent camp (castrum). It would typically be constructed alongside a ditch (fossa) and topped with a palisade made of sharpened stakes (valli). The vallum provided an elevated defensive position and protection from attack. The overall defensive system, including the vallum, fossa, and palisade, was a crucial element in Roman military engineering, allowing armies to secure their position and deter enemy action.

Specifically, the term "Vallum Aelium" refers to Hadrian's Wall, a defensive fortification built by the Roman Empire in Britain, effectively marking the northern limit of Roman Britannia. While Hadrian's Wall itself was primarily constructed of stone in its eastern sector, the earthworks and associated ditch that ran alongside it are also considered part of the overall vallum.

General Usage:

More broadly, a vallum can refer to any defensive earthen rampart or wall, regardless of its origin. In this context, it simply describes a raised embankment built for defensive purposes. The term might be used in archaeological or historical discussions of fortifications from different cultures and periods.