Despite differences in length, a paragraph and an essay have a number of similarities.
Firstly, a paragraph has a beginning which is the topic sentence that introduces the topic. Similarly, an essay has a beginning called the introduction which also introduces the key idea(s) of the essay.
Secondly, a paragraph has a body comprised of a few sentences called the developers which develop the idea introduced in the topic sentence. Similarly, an essay also has a body comprised of some paragraphs that develop the idea introduced in the introduction of the essay. A paragraph has a terminator or concluding sentence that logically draws the idea of the paragraph to a logical conclusion by restating the idea of the topic sentence. Similarly, in an essay, the concluding paragraph sums up the idea of the essay and concludes with reference to the idea(s) in the introductory paragraph. In addition to these, both have a sense of unity. The different sentences in a paragraph contribute to one idea stated in the topic sentence and thus create a sense of unity; the different paragraphs of an essay, similarly, contribute to the central argument of an essay. Thus a paragraph and an essay are largely similar structurally.
