In definition, the main point usually defines a term or concept. The main point is related to your purpose: to help your readers understand the term or concept as you are using it.

When you write your definition, do not just copy the dictionary definition; write it in your own words as you want your readers to understand it. Your topic sentence (paragraph) or thesis statement (essay) can take the following forms.

TOPIC SENTENCE:

In this example, “Class” is the larger group the term belongs to. Main-point statements do not have to include a class, however. For example:

TOPIC SENTENCE:

Now, look at this thesis statement about a related topic.

THESIS STATEMENT:

The thesis statement is broader in scope than the topic sentences, because it sets up a discussion of the larger subject of seasonal affective disorder. In contrast, the topic sentences consider one particular treatment for this disorder (phototherapy).