n.; pl. Midshipmen [ 1913 Webster ]

1. (a) Formerly, a kind of naval cadet, in a ship of war, whose business was to carry orders, messages, reports, etc., between the officers of the quarter-deck and those of the forecastle, and render other services as required. (b) In the English naval service, the second rank attained by a combatant officer after a term of service as naval cadet. Having served three and a half years in this rank, and passed an examination, he is eligible to promotion to the rank of lieutenant. (c) In the United States navy, the lowest grade of officers in line of promotion, being students or graduates of the Naval Academy awaiting promotion to the rank of ensign. [ 1913 Webster ]

2. (Zool.) An American marine fish of the genus Porichthys, allied to the toadfish; also called singingfish. [ 1913 Webster ]

Cadet midshipman, formerly a title distinguishing a cadet line officer from a cadet engineer at the U. S. Naval Academy. See under Cadet. --
Cadet midshipman, formerly, a naval cadet who had served his time, passed his examinations, and was awaiting promotion; -- now called, in the United States, midshipman; in England, sublieutenant. [ 1913 Webster ]