Supercalifragilisticexpialidocious is used as a nonsense word by children to express approval or to represent the longest word in English. In fact is a memorable fictitious word from the movie Mary Poppins (Walt Disney Studios, 1964), and also the title from a song in the movie, by Robert B. and Richard M. Sherman. It is not a real word, as the creator of the word simply created it for purpose of use in the movie. However, is used to express the fantastic and very wonderful.

The song describes how using the word is a miraculous way to talk one’s self out of difficult situations and even a way to change one’s mood. It occurs in the film’s animated sequence where Mary Poppins is harangued by reporters after winning a horse race and responds to a reporter’s claim that there are not words to describe her feelings of the moment, and her life long dream of being in theater. Mary disagrees with that claim and begins the song about one word which she can use to describe her feelings. Following the successes of the film and musical play, the word has been used as an adjective signifying rather redundant superlatives, such as “the most absolutely stunningly fantastic” of experiences.

Roots of the word have been defined, as Richard Lederer writes in his book Crazy English as follows: super- “above,” cali- “beauty,” fragilistic- “delicate,” expiali- “to atone,” and docious- “educable,” with the sum of these parts signifying roughly “Atoning for educatability through delicate beauty.