Right-bank Ukraine is a place that used to be a part of Ukraine a really long time ago. The name "right-bank" comes from the fact that it is on the right-hand side of a river called the Dnieper. This place is also sometimes called "western Ukraine."
It's important to know that Ukraine used to be split into different parts, and the right-bank was one of those parts. The people who lived there had their own culture and way of life. They spoke a different language called Ukrainian and had their own traditions.
But eventually, right-bank Ukraine became a part of Ukraine again. Even though it's still a special place with its own history and culture, it's now just a regular part of Ukraine. People still live there and speak Ukrainian, but they also share a lot of things in common with the rest of Ukraine.
So, even though "right-bank Ukraine" might sound like a really different and confusing thing, it's really just a small part of a larger country with its own unique history and culture.