Duke Definition of Plagiarism
Plagiarism occurs when a student, with intent to deceive or with reckless disregard for proper scholarly procedures, presents any information, ideas or phrasing of another as if they were his/her own and/or does not give appropriate credit to the original source. Proper scholarly procedures require that all quoted material be identified by quotation marks or indentation on the page, and the source of information and ideas, if from another, must be identified and be attributed to that source. Students are responsible for learning proper scholarly procedures.1
This suggests that there are two kinds of plagiarism: one that is committed with the intent to deceive (intentional plagiarism) and one resulting from the disregard for proper scholarly procedures (unintentional plagiarism).
Try this self-test dealing with the ability to recognize incidents of plagiarism. The examples you are about to read are drawn from actual situations that have occurred at Duke.