Regimental is an adjective meaning relating to a regiment, a large organized group of soldiers in an army - for example, a regimental flag or a regimental history. As a plural noun, 'regimentals' (old-fashioned) means a soldier's official uniform. You might also hear the word used loosely, almost like 'regimented,' to describe something done in a very strict, orderly, military-style way, though that stricter sense technically belongs to a different word, 'regimented.'

軍團的；（舊式）軍服