noun

1. a feudal servant who attended his master in battle
2. sergeant-at-arms
3. ☆
   1. U.S. Army, U.S. Marine Corps a noncommissioned officer of the fifth grade, ranking above a corporal and below a staff sergeant
   2. U.S. Air Force a noncommissioned officer of the fourth grade, ranking above airman first class and below staff sergeant
   3. generally, any of the noncommissioned officers in the U.S. armed forces with sergeant as part of the title of their rank
4. 1. in the U.S., a police officer ranking next below a captain or a lieutenant
   2. in England, a police officer ranking just below an inspector

Etymology: ME serjaunt < OFr sergant < L serviens, serving < servire, to serve