Practicing the forms of definitions may not produce writing that satisfies the informational needs of readers. This paper discusses definition as a method for engaging students in the process by which thinking and writing test and clarify one another. By first saying all he can about the theoretical and practical meaning of a term, the student can analyze his writing to discover the significances the term has for different readers and the rhetorical devices that best express the meanings. The writer then can compose a series of redefinitions of the term for different readers according to their needs.