Before Japanese fighting men were known as samurai, they were called bushi, meaning "warrior." By adding the Japanese word do, which means "the way," bushido literally translates as "the way of the warrior." It refers to a set of principles by which samurai warriors guided their lives.

Although samurai principles are usually referred to as a code of behavior, it is a mistake to think of Bushido as a precise set of rules and regulations. For centuries, ideals of honor, duty, and responsibility were not even written down. The first books about Bushido did not appear until the late seventeenth century, after the country was unified and civil wars had ceased. Writing about the code of Bushido, historian Winston L. King says:

It is too strong a term to call the samurai ethos a "code."... It was not uniform, nor was it...