- a student in training for the rank of ensign; specif., such a student at the U.S. Naval Academy at Annapolis
- a junior British naval officer ranking between naval cadet and sublieutenant
Origin of midshipmanaphetic for amidshipmen, from being amidships when on duty
- Abbr. Midn. A student training to be a commissioned naval officer, especially a student at a naval academy.
- Any of various toadfishes of the genus Porichthys found in coastal waters of the Americas, having several rows of light-producing organs along the sides of their bodies.