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where does the saying the elephant in the room come from
The Oxford English Dictionary gives the first recorded use of the phrase, as a simile, in The New York Times on June 20, 1959
What does the saying the elephant in the room mean
The elephant in the room means an important or enormous topic, problem, or risk that is obvious or that everyone knows about but no one mentions.

Question: what is the saying based on
Self-contained rewrite: What is the saying the elephan in the room based on