Definition of sergeant
1
: sergeant at arms
2
obsolete
: an officer who enforces the judgments of a court or the commands of one in authority
3
: a noncommissioned officer ranking in the army and marine corps above a corporal and below a staff sergeant;
broadly
: noncommissioned officer
4
: an officer in a police force ranking in the U.S. just below captain or sometimes lieutenant and in England just below inspector
