Exposition is explanation or background information that helps you understand a situation, story, or idea. In a novel or movie, exposition is the part where you learn who the characters are, where they live, and what problems they face. Without this setup, the rest of the story wouldn't make sense.

Think about the opening of The Wizard of Oz. Before Dorothy lands in Oz, you see her life in Kansas with Aunt Em and Uncle Henry, you meet the farmhands, and you understand why she dreams of escaping somewhere over the rainbow. That's all exposition, giving you the context you need to care about what happens next.

The word also applies outside of stories. A science teacher might begin a lesson on photosynthesis with some exposition about how plants need energy to survive. A museum guide might provide exposition about an artist's life before discussing their paintings. In an essay, exposition means explaining your topic clearly before diving into arguments or analysis.

Good exposition feels natural and interesting. Clumsy exposition feels like someone reading you an instruction manual. The challenge for writers and speakers is providing necessary background information without boring their audience or making it feel like homework.