The Elephant in the Room

When I first heard of this phrase "Elephant in the Room"… I was very anxious to know what it means.  How can an elephant fit in the room?  What’s the elephant doing inside the room?  Then a close friend told me, "It is a metaphor for something you both know is there but not willing to acknowledge."

So I tried to look for more and more definitions of it on the net. 

The elephant in the room (also elephant in the living room, elephant in the corner, elephant on the dinner table, elephant in the kitchen, and horse in the corner) is an English idiom for an obvious truth that is being ignored or goes unaddressed. It is based on the idea that an elephant in a small room would be impossible to overlook.

It sometimes is used to refer to a question or problem that is obvious, but which is ignored out of embarrassment or taboo. The idiom also implies a value judgment that the issue ought to be discussed openly.

http://en.wikipedia.org/wiki/Elephant_in_the_room

The expression "elephant in the room" refers to a situation where something major is going on, it’s on everyone’s mind and impossible to ignore — like an elephant in the room. But nobody talks about the "elephant" because nobody knows what to do about it.

http://www.phrases.org.uk/bulletin_board/6/messages/836.html

An important and obvious topic, which everyone present is aware of, but which isn’t discussed, as such discussion is considered to be uncomfortable.

http://www.phrases.org.uk/meanings/elephant-in-the-room.html