- A sign in Arabic orthography used to represent the sound of a glottal stop, transliterated in English as an apostrophe.
- A <xref>sign</xref> (<xref>ء</xref> - a stand-alone hamza) used in the <xref>written</xref> <xref>Arabic</xref> <xref>language</xref> representing a <xref>glottal stop</xref>. Hamza may appear as a stand-alone letter or most commonly over or under other letters, e.g. <xref>أ</xref> (over an <xref>alif</xref> - <xref>ا</xref>), <xref>إ</xref> (under an alif), <xref>ؤ</xref> (over a wāw - <xref>و</xref>) or <xref>ئ</xref> (over a dotless yāʾ - <xref>ى</xref>). The exact seat of hamza is governed by an orthographic rule - "seat of hamza rule".