In academic writing, it is important to avoid plagiarism. It is also important to avoid violating copyright, part of what is now generically referred to as "intellectual property". However, although there are connections, these are different issues.
Plagiarism is about presenting other people's work as your own. In an academic context this is a form of cheating. For example, if I copy a section from a textbook into an essay or article without acknowledging it, i.e. making it look like part of my own writing like the rest of the essay or article, this is plagiarism.
Intellectual property is about the right to control (and profit from) particular work. For example, if I make copies of the textbook without permission and sell them, this violates the intellectual property of the author and/or publisher.
However, these are not the same thing, and the tendency in some quarters to refer to intellectual property when discussing plagarism can cause confusion. To clarify this, let us imagine various scenarios.
|No copyright violation||Copyright violation|
|No plagiarism||1. I quote a short passage from a book, marked as a quotation by quotation marks or indenting, and indicate the source in a footnote. It is not a copyright violation because you are allowed to quote short passages. It is not plagiarism because I am not claiming to have written it.||2. I make a copy of a whole book, which is in copyright, and sell it to make money for myself. It is still labelled as being by the original author so I am not claiming to have written it.|
|Plagiarism||3. I make a copy of a whole book, which is not in copyright, and sell it to make money for myself. I change the cover to put my own name as author, so I am claiming to have written it.||4. I make a copy of a whole book, which is in copyright, and sell it to make money for myself. I change the cover to put my own name as author, so I am claiming to have written it.|
Notice the difference between the cases:
In most cases, when something is published it is "in copyright" meaning that someone has the legal right to control (and profit from) its reproduction. But some things are not in copyright. The most important cases are:
*Actually some of our material has been plagiarized extensively on the web. But we have other things to spend our time on.
Note that quoting Wikipedia without acknowldegment is plagiarism.