"Plagiarism" is the taking or attempted taking of an idea, a writing, a graphic, music composition, art or datum of another without giving proper credit and presenting or attempting to present it as one's own. It is also taking written materials of one's own that have been used for a previous course assignment and using it without reference to it in its original form.
- Taken from the CSU Undergraduate Academic Integrity Policy

The term Plagiarism comes from the Latin for kidnapper (plagiarius). Therefore, just like it is wrong to kidnap a person, it is wrong to kidnap (i.e., plagiarize) someone's work.