British English versus American English are two different languages. On top of pronouncing words differently we use different words for the same things. My first few days in England were partially spent learning and getting the hang of these words and learning to understand the British accent. Here are several words I have learned to use.
Queue – A line
Loo – Bathroom or restroom
A lie-in – Sleeping in
Uni – University
Tely – Telivision
Biscuit – Cookie
Tea – English Tea, usually with milk and sugar