(UK, nautical, military) Initialism of Her (or His) Majesty's Ship; ship prefix of the Royal Navy of the UK / Synonym of HDMS (ship of Denmark's Royal Navy)

(philately, overprint on British Empire stamps) On Her (or His) Majesty's Service.

plural of HM

A shorter variant of hmm.

Initialism of His Majesty (the title of a king). / Initialism of Her Majesty (the title of a queen). / (India, government) Initialism of Home Minister. / (military, US) Abbreviation of hospital corpsman.

(computing theory) Initialism of Hindley-Milner.

plural of HM slave

(Pokémon video games, fandom slang) A Pokémon retained by the player to use Hidden Machine moves (certain moves that usually help in exploring the world of the games).

Alternative form of HMG

(military, nautical) Initialism of His or Her Majesty's South African Ship., a ship prefix for the South African Naval Forces or its predecessor South African Division of the Royal Naval Volunteer Reserve, of the Dominion of South Africa, used from WWI through WWII