It is sometimes necessary to define one or more of the terms used in academic writing, in order to make the meaning clear, and also, in some cases, to demonstrate understanding to an examiner. While definitions will generally be only a sentence long, it is also possible to write an extended definition which covers a paragraph or even an entire essay. This page gives information on how to write a definition, language for definitions, and how to structure a definition essay or paragraph (if writing an extended definition).

How to write a definition

The most common way to write a definition in academic writing is to use a relative clause. See the following examples.

• Academic English is the branch of English which is used in formal settings, for example at university.
• Tertiary education may be defined as the period of study which is spent at university.
• A university is a place where students go to study after finishing secondary education.
• A teacher is a person who is engaged in educating students, usually at a school.

In each case, the following structure is used:

• Word to be defined + verb + category + wh-word + characteristics

In the examples above, the verbs 'is' and 'may be defined as' are used. The categories are 'branch of English', 'period of study', 'place' and 'person'. The wh-words are 'which', 'where' and 'who'. Remember that 'which' is used for objects and animals, 'where' is used for places, while 'who' is used for people.

Language for definitions

In addition to the relative clause language given above, the following phrases are useful.

• X may be defined as...
• X is concerned with...
• X deals with...
• X relates to...
• X involves...

How to structure a definition essay/paragraph

There are many ways to organise a definition essay. Some of these use structures covered on other pages, e.g. comparison, contrast and classification. Each of the following might form a single paragraph in the main body, though not all of these would be used, as the essay would be too long. If the extended definition is only one paragraph long, these could be used as supporting ideas in the paragraph.

• Etymology. The etymology (the origin of the word) is a common way to begin an extended definition. In addition to giving the origin, it can be helpful to show how the meaning or usage has changed over time.
• Exemplification. Giving examples is a common way to extend the definition of a word.
• Comparison. If the word being defined is complex, it can be compared to something which is simpler (by giving an analogy).
• Contrast. The word can be contrasted with others in the same category which are close in meaning.
• Classification. If the word being defined can be divided into different types, classification can be used to extend the definition.
• Process. If the word being defined is a process, or is used to carry out a process, then the definition can be extended by explaining the process.
• Negation. It is sometimes helpful to extend the definition of the word by explaining what it is not, in order to explain what it is.
• Description. If the word being defined is something physical, then a description of its characteristics, possibly including a diagram, might be appropriate.
• Enumeration. If the word being defined has many characteristics, then it might be helpful to enumerate (i.e. list) each of these characteristics in detail.