The way in which physical objects, like rocks and trees, have "being" differs from the way that properties of abstract concepts or relations have "being". For example, the way the concrete, particular, individuals pictured in "picture 1" exist differs from the way the concepts illustrated in "graph 1" exist. That difference accounts for the ontological usefulness of the word "abstract". The word applies to properties and relations to mark the fact that, if they exist, they do not exist in space or time, but that instances of them can exist, potentially in many different places and times.