Shiva Purana

siva.sh/siva-purana/kotirudra-samhita/28/57

तदा च प्रार्थितो मे संस्थितोसौ वृषभध्वजः।। वैद्यनाथेश्वरो नाम्ना प्रसिद्धोभूज्जगत्त्रये ।। ५७।।

sanskrit

Then, requested by me, Śiva stayed there permanently in the name of Vaidyanātheśvara. He has now become famous in the three worlds.

english translation

tadA ca prArthito me saMsthitosau vRSabhadhvajaH|| vaidyanAthezvaro nAmnA prasiddhobhUjjagattraye || 57||

hk transliteration by Sanscript