aciem

Acies is a Latin noun with primary meanings of battle line or front of an army, and also edge or sharpness. In classical Latin, the term denotes the frontline or formation of troops arrayed for combat and can also refer to the figurative edge of a blade or the sharpness of mind.

Grammatical form: acies belongs to the fifth declension; its genitive is aciei and its accusative singular is aciem, the form used in constructions such as in aciem stare (to stand on the front line) or aciem instruere (to form the battle line).

Historical usage: In Roman military doctrine, acies referred to the organized deployment of troops, famously described as the triplex acies, with front ranks of hastati, then principes, then triarii. The term also appears in poetry and prose to describe the edge of a weapon or the sharpness of an argument, extending its sense beyond the battlefield.

Modern usage and translation: Today, acies is encountered mainly in scholarly Latin, historical texts, and discussions of ancient warfare. In translation, acies is commonly rendered as “battle line” or “front line,” while aciem (the accusative) is used with verbs of placing, forming, or moving toward the line. The broader sense as edge or sharpness survives in metaphor, as in sharpness of intellect or of a blade.