Significatio vocis principes | Babel Free

Definitiones

1. the second line of the Roman army (between the first line of the hastātī and the triāriī in third and last)
   declension-3, plural, plural-only
2. nominative/accusative/vocative plural of prī̆nceps (“leader”)
   accusative, form-of, nominative, plural, vocative

Exempla

“Ab Romanis nec opus intermissum—triarii erant, qui muniebant—et ab hastatis principibusque, qui pro munitoribus intenti armatique steterunt, proelium initum.”

The works were not set aside by the Romans—triarii where there to fend off the enemy—and a fight broke out led by the hastati and principes, eager and fully-equiped, who had been placed before the workers.

Gradus CEFR