Bhagavān means the Supreme Personality of Godhead. Bhaga. Bhaga means "opulence," and vān means "one who possesses." So God means "who possesses all the opulences in fullness." He is called Bhagavān. The definition of God is "He is the richest, He is the strongest, He is the most beautiful, He is the wisest, He is the most renounced." In this way, you analyze. There are many rich men, but nobody can say that, "I am the richest of all." That is not possible, because there is competition. If I am rich, you are richer than me, another richer than you, another richer than him. So nobody can say that, "I am the richest of all." That only God can say. So in this way, where you find the Supreme, Supreme Being . . . the word God is defined in dictionary as the Supreme Being. What is that Supreme Being? The richest, the strongest, the most beautiful, the wisest, the most renounced—in this way.
So that Bhagavān, that Supreme Personality of Godhead, is speaking. Therefore, this knowledge, Bhagavad-gītā . . . Bhagavad-gītā means the knowledge given by the Supreme Personality of Godhead Himself. Not secondary knowledge; first-hand knowledge. So we have to receive first-hand perfect knowledge; then our life will be successful. Not defective knowledge. Knowledge received from a living being, as we are, that is imperfect; always imperfect—because we are deficient. We are deficient. Deficient means we commit mistake. Any big man you take, no big man can say that, "I did not commit any mistake in my life." That is not possible. He must commit. He is illusioned; he takes one thing for another. Just like big, big men nowadays at the present civilization, these all of them are accepting this body, "I am this body": "I am Indian," "I am American," "I am Canadian," "I am this, white," "I am black." But no. I am not this body. This is called illusion.