Plagiarism–handing in written work which is not your own–is a form of stealing. Other people (your teachers, fellow students, tutors in the writing lab) may give you suggestions for improving a piece of written work, but the work itself must be your own.
There are two forms of plagiarism. One is unintentional or careless when you use other writers’ words and ideas, usually in a research paper, as though they were your own. This sort of plagiarism occurs because of unfamiliarity with the conventions of documentation in academic papers; the sections on plagiarism in A Writer’s Reference (257-264) and in The Curious Researcher (80-83) should help you understand how to quote, paraphrase, and summarize the ideas of others in an acceptable manner. If you commit this kind of plagiarism, your instructor will ask you to rewrite part or all of your paper so that your sources are properly acknowledged. You can then receive credit for the paper.
The second form of plagiarism is outright cheating–turning in a paper which someone else has written and claiming it as your own, or copying sections of a book or article without proper documentation when you have had documentation forms explained to you. If an instructor finds that you have done this, she or he will contact the Director of Composition. The penalty for cheating may range from failing the paper to failing the course, depending on the evidence and the extent of the dishonesty in plagiarizing. Cases may also be referred to the University Conduct Committee, which has the power to expel students from the institution.