Lingua::Thesaurus::RelType - Relation type in a thesaurus
RelType object is just a datastructure with the following fields:
String, unique identifier for this relation type (e.g. 'NT', 'BT', 'RT', etc.)
Description string for this relation type
Unique identifier for the reciprocal relation, if any.
Boolean stating whether the item related to the lead term is another term, or is some external data (for example a "Scope Note").