Elephant is in the room

I have no idea of this phrase. But I did some surfing and I found some explanation about it.

The term is often used to describe an issue that involves a social taboo, such as race, religion, or even suicide. This idiomatic phrase is applicable when a subject is emotionally charged; and the people who might have spoken up decide that it is probably best avoided.

The idiomatic is commonly used in addiction recovery terminology to describe the reluctance of friends and family of addicted person to discuss the person’s problem. Thus aiding  the person’s denial. Especial in reference to alcohol abuse, the idiom is sometimes coupled with that of the pink elephant