definition of topic sentences
Topic Sentence Definition. Topic sentences are special sentences that serve as guideposts to the writer and reader; they help shape the essay and move it along from idea to idea. If you have already gathered information and developed some support for a thesis, you may find that your support falls into groups or categories. A rule of thumb is that you can develop a topic sentence for each category to help shape that information and to cue your reading audience in to a change in supporting idea.