This is a topic which we will probably have to return to in the future, but a start has to be made. Definitions are inextricably bound up with terms, and one classification of terms divides them up into Univocal, Equivocal, and Analogous. Let us briefly review these three classes.
- Univocal Term: A terms that has only one meaning. That is, it signifies only one concept, and thus corresponds to only one definition. Such a term always has the same intension wherever it is used. E.g. the term "entomology" signifies the study of insects.
- Equivocal Term: A term that has more than one meaning. That is, it signifies more than one concept, and thus corresponds to more than one definition. An equivocal term has different intensions when it is used. E.g. the term "chihuahua" can signify (a) a breed of dog; (b) a state of Mexico.
- Analogous Term: A term that is intended to convey one or more similar characteristics that exist between two concepts. E.g. the term "data owner" is applied to individuals who have no legal title to the data they manage, but are expected to exercise responsibilities like those owners would typically exercise. Sometimes an analogous term can be no different to an equivocal term.
It is not always easy to know if a univocal term really is univocal. For instance, I am not aware of any equivocal use of "entomology". There might be, but I am unaware of it if it exists. Also, a univocal term might become equivocal in the future.
With respect to equivocal terms, a big problem is that there are far more concepts than there are terms to describe them. This is a reason why equivocal terms come into being, and there seems to be no way to avoid it happening. From a practical point of view the problems with equivocal terms arise when a term is being used equivocally in communication. For instance, if I use "backup" within a group managing databases, everybody knows what I mean - even if " backup " has other meanings, such as in police operations.
One way round this is to maintain specialized vocabularies for "subject fields" (as the terminologists call them). Roughly speaking this means that an equivocal term can be taken to be univocal in a specific context. We will need to come back to this.
Analogous terms are more difficult. Problems include: (a) only one of the related objects is identified; (b) the characteristics supposedly in common between the two objects are never identified. This means that an analogous term may not actually signify a concept - it may be unintelligible and just used for emotive effect. It certainly implies that there is a more complex relationship between analogous terms and definitions. This too we will have to return to.