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1. Definition

Definition, "the act of stating a precise meaning" (The American Heritage Dictionary), tells

us what something is. Definition is especially important in writing because there is no

opportunity for the reader to seek clarification from the writer about the meaning of a

particular term. Therefore, the writer must clearly and precisely define the meaning of any

terms which may be ambiguous—that is, which have a double meaning—or which he thinks

the reader does not know. The lack of a needed definition, or the use of an imprecise

definition, can result in a serious breakdown in communication between writer and reader.

The writer must know his reader before he can make a decision about when to define. The

most important factor is the reader's level of knowledge. For example, the student writing a

report on thermodynamics would probably decide not to define the term thermal efficiency if

his audience consisted only of his physics professor. However, he might consider a definition

essential if the report were intended for high school students or for "lay" readers, that is, for

readers outside their particular field of expertise.

The length of a definition can range from a single word, phrase or sentence to a whole book.

Length depends on such factors as the particular complexity of the term, the reader's level of

knowledge, and the writer's purpose in defining. For students, a definition is most often a

small part of a larger piece of writing. For example, just one or two short sentence definitions

may be needed in a composition whose primary purpose is to compare two manufacturing

techniques. Sometimes, however, definition is itself the primary purpose of the writing. In

such cases, a definition could be much longer; these are generally referred to as extended

definitions.

Definitions can be classified into two principal categories according to their length:

Definitions

____________________________________

Short

Extended

____________________

Synonym/Phrase

Sentence

Short Definitions

Short definitions often consist of a single word or phrase, like those in a dictionary or they

could be the length of a sentence. They are particularly useful for defining concrete terms or

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any terms about which there is already general agreement, such as scientific terms. Writers

sometimes quote definitions directly from an authoritative dictionary or textbook. In this

case, however, quotation marks are usually used, and the source of the definition is usually

stated. Sometimes, one or two additional sentences follow a sentence definition in order to

clarify the term.

Synonym and Phrase Definitions

Underline the synonyms and phrase definitions in the following sentences:

•The field of robots is designed to give to robots visual perception (sight);

tactile capabilities (touch); dexterity (skill in handling and manipulation);

locomotion (ability to move); and navigation (intelligence to find one's way).

•Cooling towers also present environmental problems since evaporated water

can cause increased precipitation, i.e., rainfall.

•The sale of goods is an agreement by which the vendor (seller) transfers

ownership of goods to the vendee (buyer).

•Both the 30˚ and the 45˚ triangles include two edges that are orthogonal, that

is, mutually perpendicular, to each other.

•Modems, devices linking computers with each other or with information

services, are becoming increasingly powerful and sophisticated.

Sentence Definitions

One common type of sentence definition, often referred to as a formal definition, consists of

three elements:

Term

Class

Specific Differences

The term is the particular word or expression that needs defining (eg Twitter). The class is

the category to which this word belongs (eg twitter is an instant messaging system). The

specific differences are those features of the term that make it different from all the other

terms that belong in the same class (eg Twitter is an instant messaging system that allows the

user to send short text messages.). The specific differences are usually given in the relative

clause or prepositional phrase that follows the class.

Study the following sentence definitions. In each case, identify the term, class, and specific

differences. (Note that two of the definitions below have a different sequence of elements

from the others.)

•Computer hardware can be defined as the machinery and equipment used in

computer applications.

•We can define carbon footprint as the measure of carbon dioxide which is

produced by a person or organization over a given period of time.

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•A paywall is a website feature that allows access only to paying subscribers.

•The process by which a solid changes directly to a vapor without passing

through the liquid phase is called sublimation.

•A word that sounds the same as another word but is spelled differently is

known as a homophone.

Be as specific as possible when defining. For example, use adjectives to specify the class, as

in the "twitter" example above (“an instant messaging service”). Also, be sure that the

specific differences really do distinguish the term from other terms in the same class; the

definition "A chair is a four-legged piece of furniture which is usually made of wood" could

apply equally well to a table.

Avoid imprecise classes, such as "thing" or "person," which are much too general. On the

other hand, do not use highly technical words for the class or specific differences unless you

are sure your audience will understand them. A lay reader, for example, will not be helped by

a definition such as "A dictyostele is an amphiphloic siphonostele broken up into a network

of meristeles." However, a professional botanist might appreciate its precision and clarity.

Finally, whenever possible, avoid circularity, which occurs when the term and class, or term

and specific differences, are the same. A formal definition such as "A neutral solution is a

solution which is neutral" will not help the reader in any way.

Exercise 1 Identify weaknesses in the following definitions.

1. A geologist is someone who studies geology.

2. We can define a pencil as a tool for writing.

3. Inorganic substances that occur naturally in the earth are defined as minerals.

4. A thermometer is a thing for measuring heat.

5. A brunch is when you combine breakfast and lunch.

Exercise 2 Short Definitions Use your general knowledge to write short definitions of some of

the following terms. Focus on the essential characteristics of the

term: the class it belongs to and the specific differences that

distinguish it from other terms in the same class.

1. ghutra 8. vuvuzela 15. iPod

2. Facebook 9. lava 16. ecotourism

3. university 10. electron 17. WebCT

4. hybrid car 11. DN 18. climate

5. blog 12. dictionary 19. weather

6. experiment 13. flash memory 20. LOL

7. staycation 14. a spellchecker

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Extended Definitions

Often, a single sentence, or even a couple of sentences, is insufficient to clarify the meaning

of a particular term; the writer needs to go beyond merely stating its basic meaning. This is

especially true for the definition of broad abstract terms such as "education" or "success,"

where opinions may differ. New terms, like twitter, may also require extended definitions as

do many technical terms because of their particular complexity.

We can define an extended definition as any piece of writing consisting of one or more

paragraphs whose purpose is to define a particular term. A one-paragraph extended definition

often begins with a formal sentence definition which acts as the topic sentence. This sentence

is then followed by several others which extend the definition by exemplifying, partitioning,

describing, classifying, comparing, contrasting, and so on. For example, how could you write

an extended definition for the word ghutra to help a foreigner understand the word? After the

initial sentence definition, ghutra could be described in terms of its size, shape, colours and

texture. Ask yourself questions: how is it worn? What are its functions? Are there different

types? Is there a geographical spread for each type? What is known about its history? With an

extended definition, even a familiar word like ghutra requires a good deal of thought.

Exemplification is one of the commonest and most useful ways of supporting the topic

sentence of an extended definition. For example, a definition of the term "allotrope" could be

extended with examples of elements, such as carbon, which have allotropes. A definition of

the term "entropy" (a measure of spontaneous change) could be extended by giving examples

of spontaneous processes, such as ice cubes melting at room temperature or iron rusting.

Description is another common way of extending a definition. For example, a mechanism

could be described in terms of its dimensions, its parts, functions and materials. Classification

is common. For example, a definition of "natural resources" could be extended by first

classifying these resources into two basic types, renewable and nonrenewable. Analogy is

another useful tool: the term „diode,‟ for example, could be compared with a water tap in the

way the flow of electrons (water) is directed.

The following table gives just a few of the many possibilities for extending a definition:

Topic Sentence: Sentence-length definition _____________________________________________________________________________

Supporting sentences:

Examples (instances)

Illustration (extended example)

Comparison (similarities)

Contrast (differences)

Analogy (comparison of the unfamiliar with the familiar)

Etymology (origin of the term)

Exclusion (what the term is not)

Synonyms (single word with the same meaning)

Classification (division into types)

Partition (division into parts, topics, features, etc.)

Chronology (historical development)

Description (mechanism, process, place, characteristics, etc.)

Causal analysis (causes, effects)

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The following paragraph illustrates an extended definition for the term exposition. It extends

the initial formal definition in a variety of ways:

synonym definition

exemplification

etymology of the term

Term

Exposition (from the Latin exponere, meaning "to make

known" or "to reveal") is a type of writing whose primary

purpose is to inform and explain, rather than to entertain or

to persuade. For example, in writing a composition, you

might have to define a technical term for the benefit of

your "audience" (reader). You might have to classify a

number of concepts into one or two basic types, and then

describe and exemplify each type. Another composition

might require you to compare and contrast two processes,

or to examine the causes of a particular problem and then

to analyze the resulting effects. In all these cases, your

primary purpose in writing is to impart knowledge to your

reader.

The class

formal definition

(topic sentence)

exclusion

(what the term is not)

synonym definition

conclusion

(not always necessary)

Exercise 3 Model Texts Analyze the following extended definitions carefully.

In each case, identify

(1) the three elements of the formal sentence definition;

(2) the patterns of development used to extend the definition.

Example 1

Carbon footprint

The term carbon footprint can be defined as the measure of carbon

dioxide produced by a person or organization over a given period of

time. Just as a person produces a trail of footprints when he walks through

sand or mud, he also produces CO2 emissions through his normal daily

activities. For instance, apart from breathing, which is unavoidable, a large

amount of CO2 may be produced through driving to work, watching TV or

just having the lights switched on. A huge amount will be produced by

flying away on vacation. Not everybody has the same size footprint: people

living in developed countries tend to have a much larger carbon footprint

than those in less developed countries. The size of a person‟s carbon

footprint is becoming increasingly important because CO2 is a greenhouse

gas and the more we produce, the more endangered our planet becomes.

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Example 2

What is a Transmission?

A transmission is a system which carries force from one place to

another or changes its direction. Transmissions are used to carry

force and motion from the engine of a power system to the object to be

moved (the load). They can be mechanical, using parts such as gears,

pulleys, cams and levers to transmit force; hydraulic, using pressure on

a fluid such as water; or electrical, using wires to carry current from its

place of generation to the point where it will be used.

Example 3

Definition of the Term "System"

A system can be very simply defined as a group of interrelated

or interacting elements forming a unified whole. Many examples of

systems can be found in the physical and biological sciences, in modern

technology, and in human society. For example, we can talk of the

physical system of the sun and its planets, the biological system of the

human body, the technological system of an oil refinery, and the

socioeconomic system of a business organization.

Example 4

Chemical Solutions

A solution is a homogeneous mixture of a solute (substance being dissolved)

distributed through a solvent (substance doing the dissolving). Solutions exist in

any of the three physical states: gas, liquid, or solid. For example, air, the most

common gaseous solution, is a mixture of nitrogen, oxygen, and lesser amounts of

other gases. Many metal alloys are solid solutions. An example is the US "nickel"

coin, which is 25% Ni and 75% Cu. However, the most familiar solutions are those in

the liquid state, especially ones in which water is the solvent.

Example 5

The Geiger Counter

The Geiger counter is a device which detects radiation by means of the

ionization of a medium. It consists of a cylindrical metal tube filled with gas at low

pressure and a long wire along the axis of the tube. The wire is maintained at a high

positive potential (about 103 V) with respect to the tube. It works in the following

way: when a high-energy particle or photon enters the tube through a thin window at

one end, some of the atoms of the gas become ionized. The electrons removed from

the atoms are attracted toward the positive wire, and in doing so they ionize other

atoms in their path. This results in a huge number of electrons, which produces a

current pulse at the output of the tube. After the pulse is amplified, it can be either

used to trigger an electronic counter or delivered to a loudspeaker, which clicks each

time a particle is detected.

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Example 6 In the following extended definition, find examples of:

Etymology

Comparison

Chronology (historical background)

Contrast

Definition

Description

Twitter

Twitter can be defined as an instant messaging service that allows users to send and

receive short text messages instantaneously. It first started in 2006 as a type of social network to

help people keep in touch. The word itself is derived from the short high-pitched sound that a bird

makes, but which is also the word to describe silly or unimportant chatter. Tweet is the word for a

twitter message and it is also the verb form. So tweeting can be defined as the instant

communication of short messages to family and friends about everyday matters for the purpose of

informing and being informed.

It works in the following way. A user first opens an account at twitter.com, and can then start

to tweet updates to other tweeters using a computer or mobile phone. The tweeter can also follow

other users by signing up to different accounts. Twitter is comparable to other instant messaging

services provided by Skype, Microsoft and Yahoo but, unlike them, it cannot send long text

messages or provide video. In fact, the maximum length of a tweet is only 140 characters. Millions

of tweets are sent every day and some famous tweeters have many thousands of followers. Twitter

has gone beyond simple communication with friends and family and is now being used for

commercial and political purposes.

Exercise 4 Extended Definition Write extended definitions for some of the following. Begin with a

sentence definition; then add support. You may need to research

your topic using an encyclopedia, a textbook or an internet

search engine such as Google.

1. Extend some of the definitions in Exercise 2.

2. smog (etymology?)

3. Youtube

4. shisha

5. sophomore (etymology?)

6. photography (etymology?)

7. modem (etymology?)

8. atom (etymology?)

9. tsunami

10. peninsula (etymology?)

11. podcast

12. satellite

13. mirage

14. invasive species

15. catch 22

16. peer pressure

17. classification

18. polymer (etymology)

19. success

20. radar (etymology?)