illusion

An illusion is something that appears to look like something, but it actually is not.

Example: While we were hiking in the forest, we thought we saw a snake on the ground, but it was just an illusion. It was just a wooden stick.

An illusion is when someone believes in something that is not true.

Example: I always had this illusion that a girl can get pregnant just by kissing a boy.

An illusion is a trick that a magician uses to fool the audience.

Example: The coin-disappearing act was just an illusion.