Cellar door is a combination of words in the English language once characterized by J. R. R. Tolkien to have an especially beautiful sound. This observation has later, seemingly by mistake, been attributed to Edgar Allan Poe. It is also claimed that American writer H. L. Mencken once said that he had heard a Chinese student express the same appreciation for this phrase.

J. R. R. Tolkien wrote in an essay, commenting on his affection towards the Welsh language:

"Most English-speaking people...will admit that cellar door is 'beautiful', especially if dissociated from its sense (and from its spelling). More beautiful than, say, sky, and far more beautiful than beautiful. Well then, in Welsh for me cellar doors are extraordinarily frequent, and moving to the higher dimension, the words in which there is pleasure in the contemplation of the association of form and sense are abundant."

Some sources also refer to a survey, possibly conducted some 60 years ago, probing the word in the English language generally thought to be the most beautiful. Contributing to this survey, H. L. Mencken supposedly claimed that a Chinese student, who knew little or no English, especially liked the phrase cellar door — not for what it meant, but rather for how it sounded.

The phrase is also introduced in the 2001 film Donnie Darko, in which the character Ms. Pomeroy, a literature teacher, states: "A famous linguist once said that of all the phrases in the English language, of all the endless combinations of words, that cellar door was the most beautiful." In the DVD commentary, director Richard Kelly vaguely attributes this remark to Edgar Allan Poe, though no true evidence of this can be found.

Other

The production company that created the television game show Who Wants to Be a Millionaire? is called Celador.

The phrase Cellar door is also used to refer to the point where tourism meets winemaking — a shop at a winery that allows visitors to taste and buy the wine made there or using grapes from that area.