A theme is a universal lesson learned and the central idea is a one-sentence main idea.
- Central idea conveys that the text is about mainly, whereas, theme refers to the author's message, life lesson or moral learned from the story.
- A central idea cannot be referred to as the topic of the text, on the other hand, a theme cannot be same as topic.
- In one sentence, the central idea can be stated, whereas, themes are repeated and can be multiple.
Therefore, a theme is not the central idea, nor it can act as a topic of the text.