Writing your first terminological definition

energyWriting your first terminological definition might be a bit overwhelming. So how do you start? Well, many authors seem to agree that the most widely used type of definition is the intensional definition. I recommend you consult the sources below for more information as this is just a brief introduction to the subject, especially if you are going to be writing a lot of definitions for your termbase.

First, let’s review the ideas of superordinate, subordinate, and coordinate concepts. Let’s say we have three levels: The top level is superordinate and refers to the general topic (e.g. energy), the second level is subordinate and refers to those specific concepts under the general topic (e.g., (i) renewable energy or (2) nonrenewable energy) and the third level is coordinate and refers to same-level concepts (e.g., (1) wind, solar, bio, geothermal energies, etc. or (2) fossil fuels, coal, petroleum, etc.).

So, when you write an intensional definition you usually start by referring to the superordinate concept and then you describe the characteristics that make that concept unique. It’s composed of a “genus” (superordinate) and a “differentia” (delimiting characteristics), where genus is the “class of things to which the term belongs” and differentia “distinguishes it from other things in that class.” (Source 2). By the way, it was Aristotle who first introduced the concept of definition and used “genus proximum” and “differentia specifica” to define species.

Let’s take the above examples to explain this. How do we define renewable energy and nonrenewable energy?

Renewable energy

Energy that comes from resources which are naturally replenished on a human timescale such as sunlight, wind, rain, tides, waves, and geothermal heat. (Wikipedia)

Another way of writing a definition is using another comprehensive (superordinate) concept other than “energy”.

Nonrenewable energy

A resource that does not renew itself at a sufficient rate for sustainable economic extraction in meaningful human time-frames. (Wikipedia)

You might have noticed that the definition of renewable energy also presents a list of renewable energies. This is also very common and is called an “extensional definition”. So you could also make use of a definition that is extensional, i.e., you list the coordinate concepts. The easiest example to understand it is by looking at the definition of “Solar System”. Can you define it without enumerating the planets? If the answer is no, then you probably have an extensional definition (or a hybrid: intensional/extensional). In many cases, you can add the extension of your definition to your termbase as a Note field to clarify the concept.

In their article on Intensional Definitions (Source 1 below), the authors give an easy-to-follow list of the rules for writing and assessing intensional definitions. Among others, the list suggests to

  1. be precise: Include all the characteristics that make that concept unique.
  2. be concise: Make it short, don’t go overboard by giving too many unnecessary details.
  3. be objective: Make sure your definition is neutral and impartial.
  4. keep your target group in mind: are you writing for experts or laypeople?
  5. avoid circular and negative definitions: do not repeat the same idea or term and keep it real (that is, say “what a concept is, not what it is not”).

Finally, keep in mind the description given by Encyclopedia Britannica of “Intension” and “Extension”. I think it will help you get a better idea of what I just explained.

“‘intension’ indicates the internal content of a term or concept that constitutes its formal definition; and ´extension’ indicates its range of applicability by naming the particular objects that it denotes. For instance, the intension of ‘ship’ […] is ‘vehicle for conveyance on water,’ whereas its extension embraces such things as cargo ships, passenger ships, battleships, and sailing ships.”

Note: Do not confuse the homonyms “intension” with an “s” and “intention” with a “t” (purpose, goal).

Sources and further reading:

  1. Löckinger, Georg; Kockaert, Hendrik J., and Budin, Gerhard. Intensional Definitions, in Handbook of Terminology, Volume 1, edited by Hendrik J. Kockaert and Frieda Steurs.
  2. Critical Thinking: Definitions Pt. 2: Intensional vs Extensional Definitions, Genus and Differentia, Four Rules for Good Definitions”, posted by Amitabha Palmer in the blog “Mission to Transition” [consulted on July 13, 2015)
  3. Encyclopedia Britannica, Intension and extension, consulted on July 13, 2015).

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One Comment on “Writing your first terminological definition

  1. Thanks to Lexicomania that posted this comment in IMOT’s Facebook page: “It is also noteworthy that when thinking in terms of superordinates, coordinates etc that these are also relationships (PART OF, TYPE OF etc) that could be used to link our terms in a network, in some form of ontology”

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