बृहन्तो भानवो यस्य चन्द्रसूर्यादिगामिनः ।तैर्विश्वं भासयति यः सः बृहद्भानुः उच्यते ।आदिः कारणम्, स चासौ देवश्चेति आदिदेवः; द्योतनादिगुणवान्देवः ।सुरशत्रूणां पुरदारणात् पुरंदरः, 'वाचंयमपुरंदरौ च' इति पाणिनिना निपातनात् ॥
In plain words
His rays are immense; they reach into the moon, the sun, and every other light there is. By those rays he lights up the whole universe — and so he is called Bṛhadbhānu, He of Vast Rays. Ādi means cause. Dissolve the compound: he — and he is a deva — hence Ādideva, the Primal God; and deva means one in whom shining and the rest of those powers are present. Because he tears open the strongholds of the enemies of the gods, he is Puraṃdara, Breaker of Fortresses; the odd nasal in that word stands because Pāṇini himself set the form down, in the rule 'and vācaṃyama and puraṃdara'.
Close to the Sanskrit
Whose vast rays are those that reach the moon, the sun and the rest — he who by means of them illumines the whole universe, he is called Bṛhadbhānu. Ādi means cause; 'he, and he is a deva' — thus Ādideva; deva means the one possessing shining and the other such attributes. From the tearing open of the strongholds of the enemies of the gods, Puraṃdara — the form standing by Pāṇini's laying it down in 'and vācaṃyama and puraṃdara'.