Definition: a letter or a phonetic element substituted for a visarga followed by the first or the second letter of the labial class. Visarga is simply letting the breath out of the mouth. Where the visarga is followed by the first or the second letter of the labial class, its pronunciation is coloured by labial utterance. This coloured utterance cannot be made independently; hence this utterance called 'उपध्मानीय' (similar to a sound blown from the mouth) is not put in, as an independent letter, in the वर्णसमाम्नाय attributed to महेश्वर. Patañjali, however, has referred to such dependent utterances by the term अयोगवाहवर्ण. See अयेागवाह; cf. xक इति जिह्वामूलीयः । जिह्वामूलेन जन्यत्वात् । xप इत्युपध्मानीयः । उपध्मानेन जन्यत्वात्. अयेगवाह is also called अर्धविसर्ग. See अर्धविसर्ग.