Rough breathing
In the polytonic orthography of Ancient Greek, the rough breathing (Ancient Greek: δασὺ πνεῦμα, romanized: dasỳ pneûma or δασεῖα daseîa; Latin: spiritus asper) character is a diacritical mark used to indicate the presence of an /h/ sound before a vowel, diphthong, or after rho. It remained in the polytonic orthography even after the Hellenistic period, when the sound disappeared from the Greek language.