Naming the dream is a lot like giving a title to a movie. You might use the location, the action, a small piece of the action or something quite different:

Dream: I'm by the side of a river. It's a sand bank. I'm with a gang. The gang is planning a robbery. I'm not sure what on earth to do or how I got here.

The title might be "Down by the riverside", "Sand bagged", "The robbery" and so on. Usually a title comes to mind easily and gets down to the essence of what happened in the dream