Reasonably means to a fair or moderate degree, or in a way that makes sense and shows good judgment. If your teacher asks you to finish an assignment in a reasonably short time, she means you should work efficiently but she's not expecting you to rush through it in five minutes. If a store sells notebooks at reasonably priced rates, they cost about what you'd expect, not outrageously expensive but not suspiciously cheap either.

The word suggests balance and common sense. When someone acts reasonably, they're thinking clearly and not being extreme. A reasonable request is one that's fair to ask. If your friend wants to borrow your favorite book and promises to return it in a week, that's reasonable. If they want to keep it forever, that's not.

You'll also hear reasonably used to describe things that are pretty good, though not perfect. A student might say they did reasonably well on a science test, meaning they earned a solid grade even if it wasn't the highest score. Reasonably suggests something is good enough, fair enough, or sensible enough to be acceptable or satisfactory.