One Piece Encyclopedia

M-H-5 M-H-5 is Don Krieg's last resource to get the victory. It is a mortal poisonous gas that he trows from his shield.
Marutabune The Marutabune is the ship of the Kurohige Pirates.
Meitou The name given to renamed swords.
Mermaid Cafe A restaurant run by Madame Shyarly on the Coral Hill of Gyojin Island. All the waitresses are the ningyos from the Ningyos Cove. A place with a high tourist attraction, attended by many men, but which don't serve any meat.
Millions Millions are 1800 people who don't have a rank in the Baroque Works but work under the Frontier Agents (Mr. 6 - Mr. 12).
Mini Merry 2 The Thousand Sunny's "Soldier Dock System: Channel 2". A a small boat based on the Going Merry.
Miss Love Duck The Miss Love Duck is the ship of the Alvida Pirates.
Moby Dick The Moby Dick is the ship of the Shirohige Pirates.
Mugiwara Mugiwara is the Japanese word equivalent to "Straw Hat", it is the name by which is known Luffy's pirate crew and the nickname of his captain.
Mutouryuu Mutouryuu is a sword discipline that consists in fighting without swords.