186. In other compounds

In other compounds, the final alterant vowel of the first member not infrequently (especially in the Veda) lingualizes the initial s of the second: for example, yudhiṣṭhira, pitṛṣvasṛ, goṣṭhá, agniṣṭomá, anuṣṭúbh, tríṣaṁdhi, diviṣád, parameṣṭhín, abhiṣená, pitṛṣád, puruṣṭutá.

a. A very few cases occur of the same alteration after an a-element: thus, saṣtúbh, avaṣṭambha, savyaṣṭhā́, apāṣṭhā́, upaṣṭút; also √sah, when its final, by 147, becomes ṭ: thus, satrāṣā́ṭ (but satrāsā́ham).