Western Europe is one of the regions of Europe. It is a very imprecise term.
following the UN nations regions it includes:
Common region names
All the countries of Western Europe are members of European Union and NATO (except the Republic of Ireland). All but the United Kingdom use the Euro for currency. All but the UK and the Republic of Ireland are members of the Schengen Agreement , removing border checkpoints.
The region "Western Europe" is sometimes confused with the "Western Bloc", which was a Cold War name for the market-economy countries of Europe, as opposed to the Eastern Bloc of communist countries. "Western Europe" is used here more specifically.