Did You Write It?
No. Then You Better Cite It!
Wikipedia offers a very comprehensive definition. We couldnt have wrtitten better....
Plagiarism refers to the use of another's ideas, information, language, or writing, when done without proper acknowledgment of the original source. It may also include an element of dishonesty relating to an attempt to pass off the plagiarised work as original. Plagiarism is not necessarily the same as copyright infringement, which occurs when one violates copyright law. Like most terms from the area of intellectual property, plagiarism is a concept of the modern age and not really applicable to medieval or ancient works.
There is some difference of opinion over how much credit must be given when preparing a newspaper article or historical account. Generally, reference is made to original source material as much as possible, and writers avoid taking credit for others' work.
The use of mere facts, rather than works of creative expression, does not constitute plagiarism. For the latter, the issue of public domain works versus copyrighted works is irrelevant to the concept of plagiarism. For instance, it is legal for a student to copy several paragraphs (or even pages) of text from a public domain book, such as Lewis Carroll's Alice's Adventures in Wonderland, and then directly add these quotations to his or her own paper. However if these quotations were not clearly identified as to his or her source, then the student would be guilty of plagiarism, using another writer's work as if it were his or her own. High schools, colleges and universities are especially sensitive to plagiarism, and as a result, they have academic codes of ethics which prohibit plagiarism in all its forms.
Similarly, it is considered plagiarism to take the specifics of someone else's novel idea, and then present it as one's own work. This type of plagiarism frequently occurs in high schools, colleges and universities, when, for example, students use the analyses in "Cliffs Notes" and falsely present them as being their own original analysis. A small market has emerged of web sites offering essays and papers for sale to students, while a counter-industry has developed of companies offering services for instructors to compare a student's papers to a database of sources and search for potential plagiarism.
Moreover, just as there can be plagiarism without lawbreaking, it's possible to violate copyright law without plagiarizing. For example, one could distribute the full text of a current bestseller on the Internet while giving clear credit for it to the original author, financially damaging the author and publisher. In this respect, the mere fact that a piece of text is not plagiarized may not suffice to justify its use.
According to some academic ethics codes and criminal laws, a complaint of plagiarism may be initiated or proven by any person. The person originating the complaint need not be the owner of the plagiarized content, nor need there be any active or passive communication from a content owner directing that any investigation or discipline process be initiated in response to the plagiarism.
It is not plagiarism when two (or more) people independently come up with the same idea or analysis