Castrametation is a noun referring to the act of laying out a military camp. The word was first used by English naturalist Robert Plot in his 1686 Natural History of Staffordshire, in reference to Roman military strategy. It's a combination of the Latin words castra, meaning "military encampment", and metari, "to measure off". Castra (which is the source of the -cester and -chester suffix in many place names) is the plural form of the noun castrum, meaning "castle". That's thought to derive from Proto-Italic kes ("to cut") and may be related to castrare, the etymon of "castrate". Metari, meanwhile, is from Proto-Germanic metana and Proto-Indo-European med, also "measure". That composes words like accommodate, meditate, medicate, empty, modest, and others.
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