An essay is composed of several paragraphs, rather than one paragraph. In an essay, subjects can and should be treated more fully than they would be in a single-paragraph paper. The main idea or point developed in an essay is called the thesis statement or thesis sentence (rather than, as in a paragraph, the topic sentence). The thesis statement appears in the introductory paragraph, and it is then developed in the supporting paragraphs that follow. A short concluding paragraph closes the essay.