Swami Vivekananda answers the question - What is meant by knowledge? From The Complete Works of Swami Vivekananda Vol.2 page 132 - 134.
What is meant by knowledge in our common sense idea? It is only something that has become limited by our mind, that we know, and when it is beyond our mind, it is not knowledge. Now if the Absolute becomes limited by the mind, it is no more absolute; it has become finite. Everything limited by the mind becomes finite. Therefore, to know the absolute is a contradiction in terms. That is why this question has never been answered, because if it were answered, there would no more be an absolute. A God known is no more God; he has become finite like one of us. He cannot be known; He is always the unknowable one.
But what Advaita says is that God is more than knowable. This is a great fact to learn…For instance, here is a chair, it is known to us.
But what is beyond ether or whether people exist there or not is possibly unknowable. But God is neither known or unknowable in this sense. He is something still higher than known; that is what is meant by God being unknown and unknowable.
The expression is not used in the sense in which it may be said that some questions are unknown and unknowable.
God is more than known. This chair is known, but God is intensely more than that because in and through Him we have to know this chair itself. He is the witness, the eternal witness of all knowledge. Whatever we know we have to know in and through Him…He is the Essence of this ego, this I, and we cannot know anything excepting in and through that I…
Thus God is infinitely nearer to us than the chair, but yet He is infinitely higher. Neither known, nor unknown, but something infinitely higher than either. He is your Self.
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Perhaps this might be the reason why Hinduism refers to God as Brahman - meaning to expand your mind.