Final answer:
An allusion is an indirect reference to a work of literature, history, mythology, religion, or culture, while an illusion creates a false impression of reality.
Step-by-step explanation:
An allusion is an indirect or implied reference to a work of literature, history, mythology, religion, or culture. It is a literary device used by writers to add depth and meaning to their work. For example, when a poet references a character from Greek mythology in their poem, it can be considered an allusion.
On the other hand, an illusion is something that creates a false impression of reality. It is a trick of the senses, where you perceive something that is not actually there. Magic tricks often rely on illusions to deceive and entertain the audience.