The word 'pound' can mean a unit of weight. For example, a bag of sugar might weigh 5 pounds. It can also mean to hit something hard, like when you pound a nail into wood.
You pronounce 'pound' like this: 'pound' (rhymes with 'found'). It starts with a 'p' sound and ends with 'ound'.
The word 'pound' comes from the Latin word 'pondo', which means weight. It has been used in English for many years to describe weight and also to mean hitting something.