Modifier letter right half ring

The modifier letter right half ring (ʾ) is a character of the Unicode Spacing Modifier Letters range. It is used in romanization to transliterate the Semitic letter aleph and the Arabic letter hamza after it was used by The Encyclopedia of Islam (later the International Journal of Middle East Studies), representing the sound /ʔ/ (a glottal stop, as in Arabic ء hamza). In informal contexts, the backtick ⟨`⟩ or the apostrophe ⟨'⟩ is commonly used as a substitute.