Summary

A formal definition gives the class to which a term belongs and lists the characteristics that distinguish the term from other members of the same class.

Drafting

1). Choose an idea, object, or animal to explain by writing a formal definition.

2). Decide on the most specific class into which the term you have chosen fits.

3). Make a list of at least five other things that would fit into the class into which you placed the term you are defining.

4). Think about the term you are defining. List details about its appearance, that it does or is used for, or how it acts.

5). Read over your list of details. Put a check next to those details that distinguish the term you are defining from others in its class. Add any other such details that occur to you.

Composing

Use your list of distinguishing details and the class you have selected to write a definition. State the term you are defining, place it in a specific class, and add at least three distinguishing characteristics.

Revising

Read your definition carefully and ask yourself the following ques­tions:

• Into what class has the term being defined been placed? What other class, if any, would be more specific?

• Which characteristics, if any, do not distinguish the term being de­fined from others in the same class?

• Which other distinguishing characteristics might be added to the definition?

Proofreading

Proofread your definition. Follow the steps in the Proofreading Checklist on page 142. Correct any mistakes you have made in sen­tence structure, capitalization, punctuation, or spelling.

2. Writing Extended Definitions

A formal definition attempts to state as objectively as possible the characteristics that distinguish the item being defined from other things in the same class. Such a definition, however, cannot give the reader a complete picture of the item, and - especially in the case of abstract or complex ideas - definitions must be expanded if they are to be mean­ingful. Such expansions are called extended definitions.

An extended definition may be completely objective or it may in­clude the author's ideas and opinions. The ideas and opinions of the author are most likely to be included in the definition of a concept, such as courage, that different people define differently. This type of definition may be as short as a paragraph or as long as an essay or even a book. It frequently takes the form of several consecutive paragraphs in a longer work.

A formal definition of a term frequently serves as the skeleton of an. extended definition. Additional details and, in some definitions, the author's point of view and ideas serve to flesh out the skeleton. The introductory paragraph of an extended definition generally includes a formal definition of the subject and, especially when the author has a definite point of view to express, may include a thesis statement.

A variety of methods may be used in developing an extended defini­tion. For example, in an extended definition of a triangle, more infor­mation might be given by using a synonym. This synonym might be in the form of a single word or in the form of a phrase:

This simplest of all polygons has had a widespread and enduring in­fluence on human achievement.

Another way of extending the definition is by an illustrative descrip­tion of how it acts or functions:

It is of fundamental importance in architecture and engineering. If three bars are bolted together into a triangle, for example, the re­sulting structure is rigid, unlike a quadrilateral or other polygon. A framework composed of a system of triangles is therefore complete­ly rigid. The triangle is also highly important in astronomy, naviga­tion, and surveying.

Comparison and contrast are also excellent means of expanding a definition:

Like a circle and a square, the triangle is one of the most recogniz­able geometric figures. Unlike them, however, it can assume a number of shapes. It can be equilateral, it can be isosceles or scalene, and either of the latter two can be a right-angle triangle.

A metaphor can help to give the reader a new view of a familiar subject:

The triangle has been called the keystone of geometry because it is the basic figure in that discipline. A multitude of facts about other rectilinear figures have been discovered by first reducing them to their triangular components.

Finally, an extended definition can be made more interesting by a narrative illustration of the significance of your subject:

The symmetry of both the equilateral and the isosceles triangles so fascinated the ancients that many cultures adopted one or the other as a sign of perfection. Because of this association, these triangles easily became associated with divinity, eternity, and the afterlife. The pyramids of Egypt are probably the most famous example of this age-old concept, but the symbolism can still be found today in the Great Seal of the United States that is on the back of every dollar bill.

An extended definition should end with a concluding statement or section that sums up the subject and emphasizes the main idea the writer wishes to leave with the reader.