Cākṣuṣa–Vaivasvata Manvantara Transition, Deva-Gaṇa Taxonomy, and Loka-Triad Etymology
Bhūr–Antarikṣa–Dyu
नाथ इत्येष धातुर्वै धातुज्ञैः पालने स्मृतः / यस्माद्भूतस्य लोकस्य भव्यस्य भवतस्तथा
nātha ityeṣa dhāturvai dhātujñaiḥ pālane smṛtaḥ / yasmādbhūtasya lokasya bhavyasya bhavatastathā
The root “nātha,” say the knowers of roots, is remembered in the sense of protection; for he sustains the worlds of past, present, and future.