primus ordo

Literally, a first officer, this was a term used for a centurion of the first cohort, whose officers (the primi ordines) outranked the other centuriones of the legion.

Primus ordo

'First officer'. centurion of the first cohort, whose officers outranked the other centuriones of the legion.
Found on http://www.encyclo.co.uk/local/20764
No exact match found