Center for Communication Practices at Rensselaer (Formerly The Writing Center)

In the course of developing a report, essay, memo, etc. writers are often called upon to define their terms. Some of the more common definitional techniques used in professional and academic writing are described below.

• An Aristotelian or formal definition assigns a thing to a genus or class and then indicates the differences between the thing and other members of the class. Example: Craps is a gambling game played with two dice in which a first throw of 7 or 11 wins the bet; a first throw of 2, 3, or 12 loses; and a first throw of any other number (a point) must be repeated to win before a 7 is thrown--otherwise, the player loses both the bet and the dice. 
• An explication defines the meaning of key words in an Aristotelian or formal definition. An example that might follow the above definition: Dice are small cubes marked on each side with a number of small dots, varying from 1 to 6. The number of dots on opposite sides always add up to 7. 
• An operational definition refers individuals to a location or situation where they might observe a phenomenon. Example: If you are driving south along a highway, you will experience the Doppler effect if you listen to the sound of a car heading north that approaches and then passes you. 
• An analysis separates a whole into its component parts. Example: Air is a colorless, odorless, tasteless, gaseous mixture containing nitrogen, oxygen, carbon dioxide, neon, and helium. 
• An example suggests one member of a class of objects to convey an accurate impression of the entire class. Example: The maple is an example of a deciduous tree. 
• Graphics provide a pictorial representation where lines, dots, arrows, etc. are configured into representational patterns. 
• Comparisons and contrasts suggest ways in which objects or concepts are similar to or different from one another. Example: Both the maple and the pine are trees; but the former is deciduous, the latter coniferous. 
• An elimination indicates what something is not to clarify what it is. Example: Clear-cutting is not the removal of only a few trees in a forest area. 
• An etymology explores the origin and historical development of a word. Example: Synchronism can be better understood if we realize that the original meaning of syn was together, and that of chronism was time. 
• History records the events in the development of something. Example: It will be easier to understand what is meant by the discipline of technical communication if we explore how it evolved.