A more thorough explanation:

Definition: Pound sterling is the basic monetary unit of the United Kingdom. It is equal to 100 pence.

For example, if you have 5 pounds, it is the same as having 500 pence.

Pound sterling is also sometimes referred to as just "pound".

In addition to being a currency, the word "pound" can also refer to:

1. A place where impounded property is held until redeemed.
2. A place for the detention of stray animals.
3. A measure of weight equal to 16 avoirdupois ounces or 7,000 grains.

For example, if your dog gets lost and is picked up by animal control, they may take it to the pound until you can come and get it.

These additional definitions are not related to the currency definition of pound sterling.