Specification languages could aid reuse to a larger extent if they could document all important facets of software, not just functional behavior. Since a specification language designer cannot know exactly what aspects of a piece of software will be important, users should be able to do ``metaspecification''; that is, users should be able to declare new facets, and then use these facets to specify their software. Examples of facets that users might want to specify include time and space usage, safety considerations, aliasing, error checking, the user interface, etc.