“Nakama” (仲間) means comrades, friends, and people who are considered closer than family. It usually is referred to by one’s shipmates/crewmates, and the term comes up a lot when Monkey D. Luffy is talking about his crew.
Although “nakama” can be heard quite often during the original Japanese material, it is almost non-existent in the English anime and manga. However, some fans, while doing fansubs, feel that, since the word has such an impact on the show, the word nakama should remain as it is, and not be translated to something like “shipmate” or “crewmate”. Many fans who know Japanese, however, prefer the word to be translated. In a sense, it is mostly a fan-term.