Okay kiddo, so let's talk about unionism in Scotland. You know how Scotland is a part of the United Kingdom, right? It means that Scotland is connected to England, Wales, and Northern Ireland, and they all work together as one big country. Unionism is the idea that it's a good thing for Scotland to be a part of the UK and work together with the other countries.
Think of it like being part of a club. If you're in a club, like a soccer team or a chess club, you work together with all the other members to achieve a common goal. Being part of the UK is kinda like being in a club with England, Wales, and Northern Ireland. They all work together to make sure everyone in the club is taken care of.
But some people in Scotland don't think being part of the UK is a good thing. They might want Scotland to be its own country, separate from the UK. These people are called nationalists.
So, in summary, unionism in Scotland means that people think it's better for Scotland to be part of the UK and work together with the other countries, while nationalism is the idea that Scotland should be independent and separate from the UK.