There are three types of relationships: hierarchy, equivalence and association.

A hierarchical relationship shows that a particular set of ideas represented by a term contains another set of ideas represented by another term. The term representing the bigger set is a broader term, and the term representing the smaller set is a narrower term.

For example:

Broader term	Table linen
Narrower terms	Napkins
	Table Runners
	Tablecloths

When you search a broader term, you can choose to include the narrower terms in your search.

For a given idea, there is often more than one term which could be chosen to represent that idea. These are synonyms. In the Lexicon, two terms can be designated as being equivalent, i.e. representing the same set of ideas. It is possible to then choose one of these terms to be the preferred representation and the other to be non-preferred (the first is legal and the second is illegal), or they can be designated as absolutely equivalent and both usable in data entry and searching (both are legal, the second is an "alternate" term).

For example:

Preferred term	Table linen	legal
Non-preferred term	Napery	illegal
Term	Bouvier, Jacquiline	legal
Alternate term	Kennedy, Jacquiline	legal

If you search for a term which is illegal, a pop-up message can tell you what the preferred term is. If you search for a term which has any equivalent terms (non-preferred or alternate), these can be included in your search.

The third type of relationship is association. For any given term, a link can be made to other parts of the Lexicon which might be useful for a person searching this particular term. This link consists of an instruction to "See also" another term.

For example:

Term	Clothing
Related term	Dolls clothing

If you search for a term and it has a related term, the system will suggest the related term for further searching. If you search for a term and it has a related term, the system will suggest the related term for further searching.

To find out how to make these relationships between terms in the Lexicon, please consult your ARGUS manual.