Shiva Purana

siva.sh/siva-purana/rudra-samhita/6/31

अस्यानन्दवनं नाम पुराकारि पिनाकिना ।। क्षेत्रस्यानंदहेतुत्वादविमुक्तमनंतरम्।।३१।।

sanskrit

Since the holy centre is the cause of Bliss, the Pināka-bearing lord (Śiva) called it “the blissful forest” and later “Avimukta”.

english translation

asyAnandavanaM nAma purAkAri pinAkinA || kSetrasyAnaMdahetutvAdavimuktamanaMtaram||31||

hk transliteration by Sanscript