what the difference between allusion and illusion
â¢ While allusion is used to refer to something or someone else, illusion is used to refer to a false impression. â¢ Specifically, allusion means to refer to something similar or to something or somebody in the past.â¢ Illusion is a word that refers to a deception or a false impression.Images Courtesy: 1  Motion illusion in star arrangement by Fiestoforo (CC BY 3.0).s allusion and illusion both seem to sound the same when spoken in a fast manner, then the listener has to grope in the dark or search for the context in which the word was spoken to understand the meaning of the sentence.