The word pound has several meanings:

1. A unit of weight equal to 16 ounces. When you weigh yourself on a scale, you're measuring how many pounds you weigh. A bag of flour typically weighs five pounds. A newborn baby might weigh seven or eight pounds. Americans use pounds to measure weight, while most other countries use kilograms instead.
2. To hit something hard and repeatedly. When you pound a nail with a hammer, you strike it forcefully over and over. Your heart pounds in your chest when you're nervous or after running fast. Heavy rain pounds on the roof. Ocean waves pound against rocky cliffs. The word captures both the force and the repetition of the hitting.
3. The basic unit of money in the United Kingdom, similar to how Americans use dollars. If you visit London, prices will be in pounds. The symbol for the British pound is £, and one pound equals 100 pence (just like one dollar equals 100 cents).
4. A place where stray dogs and cats are taken and cared for until they can be reunited with their owners or adopted. Animal control officers bring lost pets to the pound, where their owners can hopefully find and reclaim them.