A textbook example is a perfect or ideal representation of something, often used to describe an exemplary or quintessential example of a concept, principle, or process. It serves as a model or standard against which other instances can be measured and compared. The term comes from the use of textbooks in education, where they provide clear and concise explanations of complex topics with examples that are easy to understand and remember. In this sense, "textbook example" means an exemplar that is so clear, complete, and accurate that it becomes a model for others to follow or emulate.