Through means from one end or side of something to the other end or side. When you walk through a doorway, you enter on one side and come out the other. When you read through a book, you go from the first page to the last. A tunnel goes through a mountain, and light shines through a window.

The word also describes finishing something completely. When you're through with your homework, you've completed it. When you've worked through a problem, you've solved it from start to finish. A detective works through clues to solve a mystery.

Through can mean because of or by means of. You might learn through practice, succeed through hard work, or understand something through experience. When you get through to someone, you've managed to make them understand what you're saying.

In everyday speech, through appears in many useful phrases. When you go through with a plan, you complete it despite difficulties. When you've been through something, you've experienced it. And when you're something through and through (like being “a fighter through and through”), that quality defines you completely, from the inside out.