Official title for a person appointed to report on proceedings, often in governmental, diplomatic, or committee contexts. Compare with 報告者, which is a more general term for a reporter or presenter.
See also: 報告者
The UN rapporteur reported on the human rights situation.
委員会は報告官を任命し、調査結果をまとめさせた。
The committee appointed a rapporteur and had them compile the investigation results.
Compound of 報告 (report) + 官 (official, government position). The term is a straightforward Sino-Japanese formation used in bureaucratic and diplomatic contexts.