Knowledge (concepts) in specialized domains are expressed through terminology, therefore it is essential to understand the relationship between concepts as well as to understand the relationship between concept and term. One common framework for representing concepts (and their associated terms) is to consider that concepts are related on a number of different dimensions or features. The variation of feature values is potentially infinite though most are practically discrete and restricted by interdependence with other features.

Description of concepts in specialized fields encompasses the following general types of concept:

• Entitites - material or abstract objects,
• Processes - operations and actions performed on, with or by entities,
• Properties - qualities used to differentiate among entities,
• Relations between other concepts.

Mapping concept to words can lead to dividing concepts into:

• noun concepts
• adjective concepts
• verb concepts

Relationships between concepts include:

• generic relationship - ISA - taxonomy - "is a type of", "is a kind of"
• partitive relationship - HASA - constituency - "contains", "is a part of", "consists of"

Methods of definition - in lexicography and terminology: (Sager pp42-43)

• Definition by analysis: pneumonia = an inflammation of lung tissue
• Definition by synonyms: software = logiciel
• Definition by paraphrase: whiteness = the state of being white
• Definition by synthesis (by identifying relations, by description): metatarsalgia = a painful neurallgic condition of the foot, felt in the ball of the foot and often spreading thence up the leg
• Definition by implication (by using the word in an explicative context): diagnosis = we make a diagnosis when we identify certain symptoms as characteristic of specific conditions
• Definition by denotation (by listing examples): dogs are spanials, poodles, pekinese, alsations and similar animals
• Definition by demonstration: by drawings, photographs or pointing to an object

In order for a word to be considered a specialized term, there must be general agreement (in the specialized field) that the term as defined represents the concept.

Reference

Lexicography is concerned with definition of words in general (use of) language. Lexical relationships based on concept type but must also be affected by syntactic restrictions. That is, the words "white", "whiteness" and "whiten" must be related to the same underlying concept of white, but the sentence frames (syntactic restriction) in which they may occur are different.

WordNet

The semantic relation that is represented above by @> has been called the ISA relation, or the hypernymic or superordinate relation (since it points to a hypernym or superordinate term); it goes from specific to generic and so is a generalization. Whenever it is the case that a noun Wh @-> a noun Ws , there is always an inverse relation, Ws ~-> Wh . That is to say, if Ws is the superordinate of Wh , then Wh is the subordinate or hyponym of Ws . The inverse semantic relation ~- goes from generic to specific (from superordinate to hyponym) and so is a specialization.

"In other words, database experts and lexicographers both resort to hierarchical structures for the same reason: to save space. Computer scientists call such hierarchies inheritance systems, because they think of specific items inheriting information from their generic superordinates. That is to say, all of the properties of the superordinate are assumed to be properties of the subordinate as well; instead of listing those properties redundantly with both items, they are listed only with the superordinate and a pointer from the subordinate to the superordinate is understood to mean 'for additional properties, look here.' {tree} is not the only hyponym of {plant, flora}, general terms can replace specific term (anaphora)

Hypernym is the generic term used to designate a whole class of specific instances. Y is a hypernym of X if X is a (kind of) Y. Hyponym is the generic term used to designate a member of a class. X is a hyponym of Y if X is a (kind of) Y. Coordinate words are words that have the same hypernym.

Exercise:

1. Pick a specific term, find its hypernym (more general term), i.e. Y where your term is a kind of Y.
2. Find co-ordinate terms - ie. those other things which are also Y's.

In defense of inheritance systems as a psychological reality: "They observed, for example, that it takes less time to respond True to "A canary can sing" than to "A canary can fly," and still more time is required to respond True to "A canary has skin." In this example, it is assumed that can sing is stored as a feature of canary, can fly as a feature of bird, and has skin as a feature of animal. If all three features had been stored directly as features of canary, they could all have been retrieved with equal speed."

List of 25 unique beginners for WordNet nouns:

{act, action, activity}
{natural object}
{animal, fauna}
{natural phenomenon}
{artifact}
{person, human being}
{attribute, property}
{plant, flora}
{body, corpus}
{possession}
{cognition, knowledge}
{process}
{communication}
{quantity, amount}
{event, happening}
{relation}
{feeling, emotion}
{shape}
{food}
{state, condition}
{group, collection}
{substance}
{location, place}
{time}
{motive}

"Three different kinds of distinguishing features (Miller, in press):
(1) Attributes: small, yellow
(2) Parts: beak, wings
(3) Functions: sing, fly

Each type of distinguishing feature must be treated differently.

Meronymy is obviously a complex semantic relation - or set of relations. Only three of these types of meronymy are coded in WordNet:
- Wm is a component part of Wh ;
- Wm is a member of Wh ; and
- Wm is the stuff that Wh is made from.

WordNet contains descriptive adjectives (such as big, interesting, possible) and relational adjectives (such as presidential and nuclear). A relatively small number of adjectives including former and alleged constitute the closed class of reference-modifying adjectives. Each of these classes is distinguished by the particular semantic -and syntactic properties of its adjectives.

Antonymy: The basic semantic relation among descriptive adjectives is antonymy. The importance of antonymy first became obvious from results obtained with word association tests: When the probe is a familiar adjective, the response commonly given by adult speakers is its antonym.

Semantics: Relational adjectives differ from descriptive adjectives in that they do not relate to an attribute: there is no scale of criminality or musicality on which the adjectives in criminal law and musical training express a value. The adjective and the related noun refer to the same concept, but they differ formally (morphologically).

Note that attributes are given by adjectives, parts by nouns, and functions by verbs.

Word Net is available at: http://www.cogsci.princeton.edu/~wn/

A list of dictionaries online can be found on the Library Gateway.

Further reading