allusion vs illusion: what's the difference?
An allusion is an indirect reference; an illusion is a false idea or appearance.
allusion
/əˈluʒən/
Meaning: an indirect mention of something
Example: “The title is an allusion to Shakespeare.”
illusion
/ɪˈluːʒən/
Meaning: something that looks or seems different from what it really is
Example: “an optical illusion”
How to remember
An allusion alludes (refers); an illusion is ill-founded.