This has been a popularly used expression since the mid-20th century and is still commonly used. It has recently been taken even further by English artist Banksy who has used it as inspiration for an installation. In this he has painted a large 3D elephant in the same pattern as the wallpaper in the room to highlight that even when the elephant is by far the largest object in the room people still choose to ignore it. This was particularly poignant as the exhibition centred around world poverty and thus he was keen to focus on the ignorance of many people.
This proverb is used to denote a topic which is of high importance and one which everyone in the room is aware of but one which is being purposefully ignored. This topic is generally one which is uncomfortable or awkward and thus it is being avoided.
The first recorded use of the expression dates to the year 1952 from the US publication The Charleston Gazette which reads “Chicago, that’s an old Indian word meaning get that elephant out of your room.” The meaning behind the expression in this citation is rather unclear and it is not until the year 1984 when we find it used in the same way in which it is today. This can be found in the title of a book by Typpo and Hastings; An elephant in the living room: a leader’s guide for helping children of alcoholics.
An example of this expression can be found in a quote by American author Stephen King; “how could you let such a business go on for so many years? Didn’t you see the elephant in the living room?”