Q. What is the definition for plagiarism?
From The New Dictionary of Cultural Literacy:
Literary theft. Plagiarism occurs when a writer duplicates another writer's language or ideas and then calls the work his or her own. Copyright laws protect writers' words as their legal property. To avoid the charge of plagiarism, writers take care to credit those from whom they borrow and quote. Similar theft in music or other arts is also called plagiarism.
Plagiarism. (2002). In The New Dictionary of Cultural Literacy, Houghton Mifflin. Retrieved from Credo Reference.
See "Plagiarism" in the Research 101 guide for more info.