Germanic toponymy is a way of understanding the names of places that people have given to landscapes, rivers, mountains, and towns in Europe. Just like how we have names for things and people, people in the past and present have given names to places.
A long time ago, people in Europe spoke a language called "Germanic." It was one of the many languages that people spoke at that time. When they named places, they often used words from their language. For example, if there was a place with a lot of trees, they might call it "wald," which means "forest" in Germanic. That's why we have places like "Black Forest" in Germany.
Over time, people in different places and different cultures started to mix together and share languages. This caused the names of places to change too. Sometimes, new people came in and renamed places, like how the Romans renamed a lot of places when they conquered Europe.
Today, we still have many of these Germanic place names that remind us of the past, like Amsterdam, Berlin, and Hamburg. They help us understand how people thousands of years ago saw the world around them and how they named their surroundings.