An A for effort. Cracking the books. Putting your nose to the grindstone. Have you ever heard these crazy expressions? People use them even when no one's really grading you, breaking books in two, or sharpening your nose. That's because these sayings are idioms—phrases that mean something different than what the words in them actually say. But don't let idioms make you rack your brain! Let's explore a variety of school-related idioms and figure out what people really mean when they use them.