Plagiarism is when someone uses another's work and passes it off as their own by either not citing the original author or intentionally leaving that information out. Plagiarizing someone else's work can have major implications for you as a student: from failing an assignment, to probation, and even expulsion.
When using information from a textbook, book, article, internet, etc., be sure to CITE the information in the style requested by your instructor. A good adage to remember is if in doubt, CITE IT.
Below are several links and resources to better understand plagiarism and what you can do to avoid it.