A rōnin (浪人?) was a samurai with no lord or master during the feudal period of Japan. A samurai became masterless from the death or fall of his master, or after the loss of his master's favor or privilege.
This is a nice visual glossary of all the fittings that a blade go into when creating a katana. I have studied kenjutsu and used katana’s for a number of years and never knew the proper names for all these parts.