Modifier letter left half ring
The modifier letter left half ring ⟨ʿ⟩ is a character found in Unicode in the Spacing Modifier Letters range (although it is not a modifier, but a standalone grapheme). It is used in romanization to transliterate the Semitic abjad letter ayin after it was used by The Encyclopedia of Islam (later the International Journal of Middle East Studies), representing the sound /ʕ/ (a voiced pharyngeal fricative, as in Arabic ع ʿayn).
Source: Wikipedia — Modifier letter left half ring (CC BY-SA 4.0)