A simile is a way of describing something by comparing it with something else, and you show that comparison with the words like or as. “As white as snow.” “He ran like the wind.” Those are similes. A metaphor compares too, but it does not use like or as; it speaks as if one thing were the other (“He was a lion in the match”). School English spends a lot of time on this pair, because exam papers love it. In real life people use similes all day without naming them. The word simile itself is a classroom and literature word; you will hear it from a teacher more than in the street. Say it SIM-uh-lee, three beats, stress on the first.