|Chapter 11, Verse 39|

वायुर्यमोऽग्निर्वरुणः शशाङ्कः

प्रजापतिस्त्वं प्रपितामहश्च।

नमो नमस्तेऽस्तु सहस्रकृत्वः

पुनश्च भूयोऽपि नमो नमस्ते।।11.39।।

ॐ

Transliteration / Meaning

vāyur yamo ’gnir varuṇaḥ śhaśhāṅkaḥ
prajāpatis tvaṁ prapitāmahaśh cha
namo namas te ’stu sahasra-kṛitvaḥ
punaśh cha bhūyo ’pi namo namas te

Translation

You are air, and You are the supreme controller! You are fire, You are water, and You are the moon! You are Brahma, the first living creature, and You are the great-grandfather. I therefore offer my respectful obeisances unto You a thousand times, and again and yet again!

Purport by Srila Prabhupada

The Lord is addressed here as air because the air is the most important representation of all the demigods, being all-pervasive. Arjuna also addresses Krishna as the great-grandfather because He is the father of Brahma, the first living creature in the universe.