本ほん姓せい

noun

real surname; original family name

Refers to one's true or original family name, as opposed to an alias, pen name, or married name. Often used in historical or formal contexts.

• 彼かれはペンネームを使つかっているが、本ほん姓せいは田た中なかだ。

  He uses a pen name, but his real surname is Tanaka.

• 結けっ婚こんして姓せいが変かわったが、本ほん姓せいは山やま田だです。

  My surname changed when I got married, but my original family name is Yamada.