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.-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.-in the united states navy, the lowest grade of officers in line of promotion, being graduates of the naval academy awaiting promotion to the rank of ensign.-an american marine fish of the genus porichthys, allied to the toadfish.