Understanding Knowledge Graphs: Definitions and Key Differences

Hi to everyone! As a newbie in this field, I have a really basic question about Knowledge Graphs. How would you describe what a Knowledge Graph actually is? What are its differences wrt a simple Graph? For instance, when we work with tools such as graph databases, we are  basically dealing with graphs. Then,  these databases can be used to model a knowledge graph, but their core is not inherently a knowledge graph. So, what does it take to a graph to be defined as a knowledge graph? To the best of my comprehension, a graph becomes a knowledge graph when its fundamental elements have semantic meaning. When a node represents an entity with a meaning, and when those nodes are related with a meaningful relation to humans, this is a knowledge graph. Even at this point, I struggle at making a concrete example of something that could not defined as knowledge graph, since almost every concept we, as humans, tend to connect has a meaning to us. Can someone help me clearing these concepts? Thank you!