Cākṣuṣa–Vaivasvata Manvantara Transition, Deva-Gaṇa Taxonomy, and Loka-Triad Etymology
Bhūr–Antarikṣa–Dyu
भवदित्यत्पद्यमाने काले शब्दो ऽयमुच्यते / भवनात्तु भुवल्लोको निरुत्तया हि निरुच्यते
bhavadityatpadyamāne kāle śabdo 'yamucyate / bhavanāttu bhuvalloko niruttayā hi nirucyate
When ‘bhavat’ comes into being in its proper time, this word is uttered. From ‘bhavana’ the realm called ‘bhuvaḥ’ is explained according to nirukta.