ＯＢ

noun

alumnus; former member; old boy

Refers to a former member of a school, company, team, or organization. Often used in contexts like 大学のＯＢ (university alumni) or 会社のＯＢ (former company employee).

See also: オールドボーイ

• 彼かれはこの大だい学がくのＯＢです。

  He is an alumnus of this university.

• 会かい社しゃのＯＢが集あつまって同どう窓そう会かいを開ひらいた。

  Former employees of the company gathered and held a reunion.

noun

out of bounds

Golf term; used when a ball goes outside the playable area. Also used metaphorically in other contexts to mean something is off-limits.

• ボールがＯＢになった。

  The ball went out of bounds.

• その話わ題だいはこの会かい議ぎではＯＢだ。

  That topic is out of bounds in this meeting.