Noun
nanori (plural nanori)
(linguistics) A Japanese reading of a kanji character that is used for names of people or places, but that is otherwise a non-standard reading for that character.
Other readings Some kanji also have lesser-known readings called nanori (名乗り), which are mostly used for names (often given names ) and in general, are closely related to the kun'yomi. Source: Internet
Samurai could choose their own nanori, and frequently changed their names to reflect their allegiances. Source: Internet