Usage Privilege
Any user can reference a built-in data type in an SQL statement, but not a DISTINCT data type that is based on a built-in data type. The creator of a user-defined data type or a DBA must explicitly grant the Usage privilege on the UDT, including a DISTINCT data type based on a built-in data type.
REVOKE with the USAGE ON TYPE keywords removes the Usage privilege that you granted earlier to another user, to PUBLIC, or to a role.
The following statement revokes from user mark the privilege
of using the widget user-defined type:
REVOKE USAGE ON TYPE widget FROM mark;