When we use the word "Enlightenment", does that mean the same as "Acquiring Greater Knowledge"?

No. Enlightenment is the first glimpse of the absolute. The revealing of the interconnection of all things. All things being one and all things effecting all other things, ( in the physical world that is). All things connected by the invisible effects of the spirit consciousness that ultimately is God. This recognition then opens the doorways to the infinite knowledge which is held within consciousness. Thus in time, one who has enlightenment, has gained greater knowledge. And that is endless and infinite.

It depends on the context and the use. If you are refering the the historical period known as "The Enlightenment" you are refering to a dialect in modern philosophy which privileges the possibilities of human reason over against the alleged obscurantism of tradition and revelation. If you are applying the word to one's own knowledge, I would say an experience of enlightenment is one in which the illumination of truth or understanding overcomes the darkness of ignorance. In this respect, you could also say that it represents the acquisition of greater knowledge.

Depends what you mean by enlightenment. If you're talking about 'the Enlightenment' then you're talking about a period of history where people rejected myth and tried to base everything on reason (eg Kant). If you're talking about 'achieving enlightenment' then it's more of a mythical or religious concept (see other answers). But people use it in slang to mean acquiring greater knowledge (often this is done sarcastically: "guess what gross thing I found today?" "enlighten me.")

I don't look at is as gaining knowledge. When I think of enlightenment, I think in terms of self discovery...it is more internal than external.

Not necessarily a Christian concept. Many religious/cultural groups have used meditation as a means of reaching spiritual enlightenment.

Probably learning coupled with thinking...how what you have learned applies to you and to the greater world/Universe...

Enlightenment is the process by which we learn about the creator of all that exists and the part of ourselves that is eternal. I stress the word process because Enlightenment is not a destination. There are always great and deeper understandings that permit us to understand "the depths of God." (1 Corinthians 2:10). As Paramahansa Yogananda points out this knowledge must be self-realized in the deepest core of your being, "Self-realization is the knowing in all parts of body, mind, and soul that you are now in possession of the kingdom of God; that you do not have to pray that it come to you; that God’s omnipresence is your omnipresence; and that all that you need to do is improve your knowing.”

Enlightment means 'achieved the ultimate understanding'. You have lot of whys and hows in life. If you find an answer that ultimately ends all these and further questions .. you are enlighted. Budha started his quest to find out the reason behind suffering( disease, death and old age). His enlightment was 'There are only causes of suffering. One is being away from what one want and another is being tied to what one does not want. The basis of both of these is desire (want to be with/ hate to be with)'. This is very logical.

This applies to all questions. Enlightment is the answer - you get a perfect reason that explains the cause and effect.

You acquire greater knowledge to REACH enlightenment.....

Enlightenment Is when we realize that everything that we thought that we knew was wrong.

no, quite the opposite

if you are referring to Buddhist enlightenment

I think it would mean deeper or hidden truth coming to light, which is not apparent superficially.