The language roots stem from the adjective "limus" (lateral) and
"-it" (moving). "Limes, limitis", masculine, thus referred to a
prepared path. In surveying, the term "limes" meant the path
between two properties (source: Frontinus, Hyginus).
In military usage, the term first referred to deforested aisles which were later followed by controlled roads, which in turn led to the conquest of territory (source: Sextus Julius Frontinus, military scribe in the 1st century, on the Chatti War.
The current use of the "Limes" as a military border is based on a concept from the end of the 1st century AD. "Limites imperii et ripae" are mentioned by Tacitus (Agricola, Germania). The term continued to be used as reference to the frontier in late antiquity, for example in the administrative list notitia dignitatum which mentioned "milites limitanei et riparinenses".
Limes-Lexikon 2009, 79 s.v. Limes
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