What is an exchange rate?
An exchange rate is just a price: the price of one country’s currency in terms of another country’s currency.
So if the exchange rate from UK pounds to US dollars is 1.35, then £1 will buy you $1.35.
Sometimes you will hear that the pound has got stronger or ‘appreciated’. These are just two different ways of saying that the price of the pound has risen compared to another currency.
For example, the pound strengthened against the dollar from 2000 to 2008 before falling sharply (‘weakening’) back to early 2000 levels: