サインボール

noun

autographed baseball; signed ball

Refers specifically to a baseball that has been signed, typically by a player. A wasei-eigo term; in English one would say 'signed baseball' or 'autographed baseball'.

wasei-eigo (Japanese-coined English), from sign ball

• 彼かれは大おお谷たに選せん手しゅのサインボールを宝たから物ものにしている。

  He treasures an autographed baseball from Ohtani.

• サインボールをもらうために、試し合あい後ごも球きゅう場じょうで待まっていた。

  I waited at the stadium after the game to get a signed ball.