There should be a strong connection between your conclusion and your introduction. All the themes and issues that you raised in your introduction must be referred to again in one way or another. If you find out at this stage that your thesis has not tackled an issue that you raised in the introduction, you should go back to the introduction and delete the reference to that issue. An elegant way to structure the text is to use the same textual figure or case in the beginning as well as in the end. When the figure returns in the final section, it will have taken on a new and richer meaning through the insights you have encountered, created in the process of writing.
The second way one uses the word "thesis" is in reference to a major paper that one writes as a capstone for his or her bachelor's or master's degree. Whereas term papers are projects that last one term, theses are projects that last several terms. Theses are usually much, much longer than term papers, often stretching past two hundred pages. Perhaps counterintuitively, however, theses often cover much more specialized topics than term papers. For example, one may write a term paper on Herman Melville for a literature survey course, but one would be much more likely to write a thesis on homosexual symbolism in Herman Melville's Moby Dick or on some other extremely specific aspect of one of Melville's novels. In fact, one could write an entire thesis on a single paragraph of Moby Dick . The goal of a thesis is to expound fully one's opinion on a given subject and to confront and exhaust all the opposition to that opinion. Therefore, one usually specializes his or her thesis topic almost to the point of absurdity.