Illustrated Companion to the Latin Dictionary/Castrum

This article incorporates text from a publication now in the public domain: Rich, Anthony (1849). The illustrated companion to the Latin dictionary, and Greek lexicon. p. vi. OCLC 894670115. https://archive.org/details/illustratedcompa00rich. 

CASTRUM. An augmentative of CASA, meaning in its primary sense a large or strongly-built hut, and thence a fort or fortress; though the diminutive CASTELLUM was retained in more common use. Nepos, Alcib. 9. Virg. Aen. vi. 776.