main sheet – a line used to control the mainsail.
man-of-war – traditionally, any ship whose main purpose was combat. Later on the term came to mean a particular class of large, powerful sailing ships with three decks of guns.
mariner – a sailor
maroon – a form of punishment involving stranding a captive on a deserted island with few or no supplies. According to legend, the one exception might be the offer of a pistol so that the victim could choose to commit suicide rather than die slowly.
masthead – the top of a mast.
matey – an informal form of the word mate, meaning shipmate, friend, buddy, etc.
me – my.
merchant – a ship carrying goods for commercial purposes, as opposed to a ship belonging to the government of a country or to a pirate.
mizzen – the third mast, as counted starting at the front of the ship
monkey jacket – a coat cut to a shorter length than those normally worn to allow freedom of movement in the rigging.
mutiny – an act of rebellion against a ships captain (or officer class) by subordinates. Mutineers risked the death penalty, often by hanging.
