古罗马兵营（拉丁语：Castra，音译卡斯特拉，单数格式castrum）是古罗马人用作军事防御阵地而构建的建筑物或预留的地块。这个词在奥斯坎语和翁布里亚语都出现。在古典拉丁语中，根据雷纳特斯的解释，Castra的意思是“大的军团营地”，也包含了行军，临时和永久防御的意思，小词缀形式的castellum通常但有时并非如此用于表示较小的堡垒，被辅助部门占用，作为军团的物流基地。在英语中，术语Roman fortress，Roman fort和Roman camp通常指Castra。然而学术界趋于使用camp，marching camp和fortress作为Castra的翻译。这些惯例通常被遵循并使用在学术著作中。

In the Roman Empire, the Latin word castra (singular castrum) were buildings or plots of land reserved for or constructed for use as a military defensive position. This term appears in three Italic languages: Oscan, Umbrian and Latin. In classical Latin the word castra means "great legionary encampment" and included "marching", "temporary" and "fortified permanent" ones, while the diminutive form castellum was used for the smaller forts, which were usually, but not always, occupied by the auxiliary units and used as logistic bases for the legions, as explained by Publius Flavius Vegetius Renatus. A generic term is praesidium ("guard post or garrison"). The terms stratopedon ("army camp") and phrourion ("fortification") were used by Greek language authors to translate castra and castellum, respectively.