How to Write Definitions

Formal definitions are based on logical and concise patterns. A definition requires you to provide as much information as you can, as briefly as possible. The main purpose of definitions is to eliminate misunderstanding. Check out this guide from College Writers to learn more about definitions.

A formal definition includes three key parts:

• the word (term) that should be defined;
• the concept or class to which this word belongs;
• characteristics that make it unique and different from other things that belong to the same class.

For example, here is a definition of water:

• Water (term) is a liquid (class), which molecules consist of oxygen atoms and twice as many hydrogen atoms.

This example illustrates the structure of a definition. However, most people already know what water is, so you should clearly understand whether or not you need to provide a definition, in the first place.

When to Use Definitions

• When your readers should understand some terms to understand the meaning of your content and these terms may be unfamiliar to them.
• When a certain phrase or word may be interpreted subjectively or have multiple meanings and you want to define them.
• When the origin or history of a common term can help you support your point or are relevant in the context of your work.

Additional Tips

• Don’t provide definitions that begin with “X is where…” Avoid such adverb phrases. We suggest that you define nouns using nouns and verbs using verbs.
• Avoid repetition, such as “Rhyming poetry implies using lines that rhyme with each other.”
• Use simple and familiar words. You don’t want your audience to look for more definitions to understand your definition.
• When describing the class, don’t make this part of your definition too wordy. However, this part should be large enough to explain the main features of this class. Don’t add personal details to your definitions and don’t try to explain some term using your personal experience. In this case, your readers will only more likely to misinterpret your words.