The major point of a paragraph is often called the controlling idea. Every paragraph should have a different controlling idea, each one discussing one aspect or part of the overall essay.
Body paragraphs will often begin with a summary of the controlling idea: the topic sentence. The topic sentence summarises the paragraph in the same way that the thesis statement summarises the whole essay.
The rest of the paragraph supports that topic sentence, by explaining it in detail, giving an example, or citing evidence that reinforces it.