na-ka-ma - 仲間 - Japanese
A fair bit of conjecture exists in the English speaking world about this word and how to translate it. Some have said it cannot be adequately translated into a single, elegant English word.
Basically, the direct translation from Japanese is along the lines of "friend, partner, associate", but the actual usage of the word differs to these rigid examples. You might refer to a work collegue as nakama, however it also indicates a much closer relationship than the traditional workmate. It almost borders on the closeness of family except, used in that sense, nakama is far too formal.
Matters are complicated further by the word's use in anime, especially One Piece. A pirate crew, who has been together through thick and thin, the good times and the bad, and stayed loyal and faithful to each other, are nakama. Here the word's meaning takes on a whole new angle, building on a "group of friends", or a "band of brothers" of sorts. So perhaps suggestions of "buddy", in its most genuine sense, or "mate", in the way, say, Australians like to use it, might suffice?
Take, for instance, a scene in One Piece where Luffy, the captain of the crew, shouts to his endangered navigator Nami "You are my nakama!!". The intensity and passion in his line wouldn't sound right behind "You are my buddy!" and certainly goes far beyond any casual, throw-away buddy / mate / pal friendliness.
In the majority of RPG games (such as the Final Fantasy series) that are translated from Japanese to English, when a new member joins your gang the game announces "So-and-so has joined your party!", whereas the original language declares this new character your nakama.
Essentially, in Japan this word means any of these examples. Most likely used and understood in the "friend, colleague, group member" sense, it can be interpreted in a number of ways because Japanese is less firm, and more creative, than English in their definition of words. In English, to translate this word would rely on the given situation. A frequently brought up example of an adequate translation is the word "comrade", which, although developing a close bond that friendship and family can't quite describe, doesn't appeal to everybody searching for a perfect definition.