Boyd’s Bible Dictionary:
Tenth part of a Roman legion; called also “cohort” (Matt. 27:27; Acts 21:31).
Strong’s Dictionary of Greek Words:
Meaning:
of immediate Latin origin, but ultimately a derivative of 138 in the sense of its cognate 1507; a coil (spira, "spire"), i.e. (figuratively) a mass of men (a Roman military cohort; also (by analogy) a squad of Levitical janitors)