How Arjuna Addresses Kṛṣṇa in the Gītā
In XI.41 Arjuna begs forgiveness for (among other things) having used familiar language in addressing the Lord: ‘Kṛṣṇa’ ‘Yādava’ (descendent of the Yadu tribe, equivalent to ‘Scotty’, etc.) This, and the change after seeing the Universal Form, are illustrated by the terms in the Gītā itself.
Acyuta = firm one (also lit. not leaking away, not falling, etc.)
Kṛṣṇa (lit. black)
Keśava (lit. hairy)
Govinda – cow-herd
Madhu-sūdana – slayer of demon Madhu
Janārdana – jana (men) ardana (distributer); excitant, stimulator, nuisance, gadfly
Mādhava: related to spring, vernal; descendant of Madhu
Vārṣṇiya – Vṛṣṇi clansman
‘Best of men’, Puruṣottama (no Śankara comment: not supreme Spirit here)
Supreme Brahman, supreme Light, supreme Purifier; eternal divine Puruṣa, primal God, unborn Omnipresent
Puruṣottama (here supreme Spirit), source of beings, Lord of beings, God of gods, ruler of the world
Supreme Lord (parameśvara), supreme Spirit
Description of Universal Form
O Lord of Gods, abode of universe
O Lord Supreme
Hṛṣikeśa (lord of the senses)
Mighty Being, primal Cause, infinite Being, Lord of gods, abode of universe, imperishable, Being-not-being, supreme Lord of gods
Primal God, ancient Puruṣa, supreme abode of all, knower and knowable and supreme abode, all-pervading, of infinite forms
Infinite in power, infinite in daring
Greatest Father of the world, etc.
guru (only time this word used in Gītā for spiritual teacher, though Bhīṣma and Droṇa are gurus of strategy, archery, etc.
Here in XI.43 it refers to the Universal Form which terrifies Arjuna and which he asks to be removed.
God of gods, abode of universe
Thousand-armed, Universal Form
Slayer of demon Keśin