noun
supplementary biography
A biographical work that supplements a main biography (本伝). Often used in historical or literary contexts.
See also: 本伝
この外伝は、本伝に書かれなかったエピソードを集めている。
This supplementary biography collects episodes not included in the main biography.
noun
A story that branches off from a main work, such as a novel, film, or game. Can also refer to an anecdote or a tale about a side character.
人気ゲームの外伝が来月発売される。
A spin-off of the popular game will be released next month.
彼は旅先での外伝を面白おかしく話した。
He amusingly told anecdotes from his travels.
From 外 (outside, external) + 伝 (tradition, biography). The compound originally referred to a supplementary biography outside the main biographical tradition.