This is an abstract superclass. It's child classes are used to define classes and enumerations which are not part of the SAIF standard.
type: the name of the class or enumeration and the schema from which it is taken are defined.
tag: the tagCategory and tagNumber are provided. Taken together they provide a unique means of distinguishing the type from all other possible types in a transfer, in encoding schemes which require the use of tags. Note that if tags are not required by the encoding scheme, it is best not to use them. (A tag value need not be entered if SAIF/ZIP is being used.)
The high level structure of TypeDefinition is diagrammed below.