However, "expository" describes a type of writing or speech. Expository writing aims to inform, explain, or clarify a topic.
Expository sentences are simply sentences that contribute to this explanation. They could be:
* Defining terms: "A palindrome is a word or phrase that reads the same backward as forward."
* Providing facts: "The Earth is approximately 4.54 billion years old."
* Explaining processes: "To bake a cake, you first need to preheat the oven."
* Analyzing ideas: "The novel's protagonist is a complex character who struggles with both internal and external conflicts."
In essence, any sentence that helps to explain a topic, provide information, or clarify a concept can be considered an expository sentence.