Allude to an illusion

If you’re not careful with the pronunciation, allusion and illusion can sound very similar, and they are occasionally incorrectly swapped for each other.

An illusion is not real; so someone may have a false idea or see something that isn’t really there – they are facing an illusion.

Allusion is a reference to knowledge you assume your reader/listener understands, especially when referring to literary or art knowledge. For instance, I will make an allusion to Shakespeare’s work when I write: the young couple considered themselves to be as tragic as Romeo and Juliet. I can assume that most people know the story of Romeo and Juliet so the allusion explains a lot in few words.

To remember which is which, consider that illusion starts with I and often relates to a trick of the eye. Allusion starts with A and usually relates to Art and literature.