Although design notations are increasingly being given a formal semantics, often the notations are only informally related to their semantic models. This may be because graphical design notations cannot directly be given an abstract syntax using the well studied string grammars. The paper proposes the use of node-labelled controlled graph grammars to define the abstract syntax of graphical design notations. To illustrate this approach a simple twelve rule grammar is given for a subset of the MASCOT design notation.