Customizing the metamodel : Definitions: Creating and modifying : Assigning a definition type to a symbol type
  
Assigning a definition type to a symbol type
If you add new symbols to an encyclopedia in USRPROPS.TXT, you must specify what definition type they are associated with using this keyword. If a new symbol specified in USRPROPS.TXT is missing this clause, System Architect will give a parsing warning when opening the encyclopedia, and default to the null definition for the symbol, which consists simply of the Description property.
SYMBOL "My Symbol"
{
DEFINED BY " My Definition"
ASSIGN TO "My Diagram"
}
Example
In the example below, the symbol type “Satellite” is specified to be defined by the definition type “Satellite” (the fact that they happen to share the same name is not enough).
Rename Diagram "User 1" TO "Wireless Network"
Rename Symbol "User 1" TO "Satellite"
Rename Definition "User 1" TO "Satellite"
SYMBOL "Satellite" { DEFINED BY "Satellite" ASSIGN To "Wireless Network" }