According to the Merriam-Webster's Learner's Dictionary, plagiarism is "the act of using another person's words or ideas without giving credit to that person."
Copying word for word or phrases whether oral, printed, or on the internet, without citing the source
Borrowing facts, statistics, graphs, or other visual material without citing the source
Turning in someone else's work with your name on it.
Not putting quotation marks around quotes
Paraphrasing text without citing the source
Giving incorrect information about a source
How do you prevent plagiarism?
Remember to take good notes and keep track of your sources as you use them. This includes web addresses, books, articles, journals, etc.. Keeping track of your sources as you use them will also make it easier to create your bibliography.