Industrial Revolution: A period from 1750s-1850s when major changes in agriculture, manufacturing, mining, transport impacted socio-economic conditions in Britain first before spreading worldwide. Like going from handwritten essays to typing them on computers overnight!
Commonwealth: An intergovernmental organization of 54 member states that are mostly former territories of the British Empire. It's like a club formed by ex-students of the same school.
Brexit: The withdrawal of the United Kingdom from the European Union and the European Atomic Energy Community. Imagine quitting a sports team because you don't agree with its rules or strategies.