Scalar - modelint/shlaer-mellor-metamodel GitHub Wiki

This is the name of some Type such as Integer, Pressure, Height, Counter, Nominal, Ordinal, Regular Expression, etc. defined in a separate modeled or realized Domain devoted to non-relational type definition. We defer all non-relational type definition to a separate typing system since there is nothing Shlaer-Mellor specific about this subject matter. But we do, in our metamodeling domain, need to know what things are typed and how.

It may help to think of a Scalar type as a key to some definition found in a separate type system. This key will lead you to all supported operations, type inheritance, and all that good stuff.