Pirate

A Pirate in the world of One Piece is anyone, Man Woman or Child, who raises a Jolly Rodger, whether they commit an act of Piracy or not. THis is not, however, enough to give anyone a bounty. There are two types of Pirates in One Piece, but the terms were only in the original Romance Dawn chapter, and have not yet been mentioned in the current version of One Piece.

Mountain Bandits are said to be the opposite of Pirates and have not been know to get along with each other too well.

Peace Maine
Described in Romance Dawn Version 1, A Peace Maine is a Pirate who goes on adventures, and doesn't really care about personal treasures or going aorund fighting other Pirates. Luffy is a reall good example of a Peace Maine.

Morgania
The Morgania fight for treasure and personal gain. They are greedy and love to fight just to cause other people pain and misery. Most of the other Pirates Luffy and his Crew meet are Morgania. Luffy dislikes Morgania and only wants to recruit Peace Maine Pirates.