Under is a word that describes being below something else or beneath it. When you crawl under a table during a game of hide-and-seek, you're positioning yourself in the space below the table's surface. When a submarine travels under the ocean, it moves through the water beneath the waves.

The word also means less than a certain amount or level. If a sign says “children under 12 eat free,” it means kids who haven't reached their twelfth birthday yet. When a recipe calls for under five minutes of cooking time, it means less than five minutes.

Under can describe being controlled by someone or something. Students work under their teacher's guidance. A knight in medieval times served under a king. When you're under pressure, you feel stress pushing down on you, and when you're under the weather, you're feeling sick.

The word shows up in many useful phrases: going under water, staying under budget, or keeping something under wraps (keeping it secret). The opposite of under is usually over, which means above or more than. Understanding where things sit in relation to each other, whether physically or in amount, helps you describe the world more precisely.