Daco-Thracian is a word used to describe two ancient groups of people who lived in a region called Thrace.
Think of it like this: imagine you and your friends live in a really big playground, and there are two groups of you - the Daco group and the Thracian group. You all speak different languages and have different customs, but you live next to each other and sometimes have to work together.
The Daco group lived in an area called Dacia, which is now Romania, and the Thracian group lived in an area that is now parts of Bulgaria, Greece, and Turkey. They were both very brave and proud of their cultures, and they often fought with each other because they wanted their group to be the strongest.
But even though they fought a lot, the Daco-Thracian people also shared some things in common. They both believed in gods and goddesses, and they both liked to make beautiful art and jewelry from gold and other precious materials. They also had their own ways of farming and trading goods, and they learned from each other over time.
So Daco-Thracian is a word that helps people understand these two groups of ancient people who were different from each other, but also had things in common, just like you and your friends on the playground might be different, but you all have things you share and things you do together.