What does the latin word centurion mean?

Answer 1

In the Roman Army a centurion was a junior officer in charge of 80 men. This had archaically been 100 men (a century) but by the early Empire it had reduced to 80 - the centurion took his title from the word centuria - a century.

Each cohort had 6 centuries (5 double-sized centuries in the 1st cohort) and there were 10 cohorts per legion, giving a total of 59 centurions per legion. The most senior was the Primus pilus, who was often promoted into a higher administrative position after a year in that rank.

Within each century one man was chosen as Optio, an officer-cadet who would later take over when his centurion retired or was promoted.