Is the word supercalifragilisticespialadoshes a real word?

No, the word "supercalifragilisticespialadoshes" is not a real word in the sense of being a word with a recognized definition and usage in a language. It is a fictional word created by the screenwriters of the 1964 musical film "Mary Poppins" for use in the song "Supercalifragilisticexpialidocious."