Dated term for Islam; modern Japanese prefers イスラム教 or イスラーム. Still encountered in older texts.
See also: イスラム教
In prewar literature, the notation '回教' was often used.
Islamic nation; Muslim country
mosque
From 回 (hui, referring to the Hui people or Islam in Chinese) + 教 (religion). The term was adopted in Japanese as a name for Islam, but is now considered dated.