- U.S. Army, Air Force, and Marine Corps. a noncommissioned officer serving as chief administrative assistant in a unit headquarters.
- U.S. Marine Corps. a noncommissioned officer ranking above a first sergeant.
- a small damselfish, Abudefduf saxatilis, inhabiting warm Atlantic waters, having vertical black stripes on each side.
- a noncommissioned officer of the highest rank or having specific administrative tasks in branches of the armed forces of various countries
- a large damselfish, Abudefduf saxatilis, having a bluish-grey body marked with black stripes