Hey! That's actually a pretty common misconception people have about GraphQL when they first hear about it - however, GraphQL definitely is not a Graph database (as is Neo4j). In fact, it's not even a database technology, despite sharing the same suffix with SQL!
GraphQL is a query language for APIs - so, the closest you could get is to say that GraphQL is an API technology! It defines a specific request/response-format for client-server communication that's extremely flexible, simple and efficient. GraphQL is also independent of the transport protocol that's used (though mostly that's HTTP today).