To finalize something means to complete it and make it officially ready. When your teacher finalizes the schedule for a field trip, she's done planning and has settled all the details: the bus is booked, permission slips are ready, and the date is set. Nothing major will change now.

You might finalize a book report by checking it one last time before turning it in, or your family might finalize vacation plans after everyone agrees on where to stay and what to do. Scientists finalize their research findings before publishing them, making sure every measurement is correct and every conclusion is sound.

The word suggests completion with a sense of making something official or permanent. When you finalize something, you're moving it from “still working on it” to “done and decided.” A rough draft isn't finalized; a published version is. Once something is finalized, people can count on it and make their own plans around it.