A graphical presentation of a collection of model elements, most often rendered as a connected graph of arcs (relationships) and vertices (other model elements). UML supports a number of kinds of diagram.
See also background information, font usage, hyperlink, keyword, label, package, path, presentation element, property string.
A diagram is not a semantic element. A diagram shows presentations of semantic model elements, but their meaning is unaffected by the way they are presented.
Most UML diagrams and some complex symbols are graphs that contain shapes connected by paths. The information is mostly in the topology, not in the size or placement of the symbols (there are some exceptions, such as a timing diagram). ...