Plagiarism is representing another person's work as your own. "Another person's work" includes written papers, oral works, music, media, art, ideas, and computer-based work. The work can be published or unpublished. Some types of plagiarism - such as purchasing a paper from a website, or "borrowing" a paper your roommate wrote last semester - are obvious infractions of the academic integrity code. However, it is also possible to plagiarize on accident.
That's right, you can ACCIDENTALLY plagiarize!!
But how?? Failure to properly cite information you use from a source is plagiarism. It is very important that you understand how to properly cite. You will write many research papers during your time as a college student. Once you understand how to properly cite information, you can write research papers with the confidence that you will not find yourself in trouble for accidental plagiarism.
Information that is common knowledge does not need to be cited. Common knowledge includes facts such as dates or locations of historic events, and common sayings and proverbs (ex: "All that giltters is not gold."). Information that is common knowledge can be found in 5 independent sources.
Not sure? When in doubt, cite! It is better to cite something that you did not need to cite than to not cite something that should be cited!