The Oxford English Dictionary defines plagiarism as:
"The action or practice of taking someone else's work, idea, etc., and passing it off as one's own; literary theft."
To avoid plagiarism, the APA recommends using citations in these cases:
(Publication manual of the American Psychological Association: the official guide to APA style, p. 255.)
Self-plagiarism is using your own written work that you have already submitted for another class or another assignment. If you are "double-dipping," you need to cite your previous paper and also include it on your reference page. Since you are not an expert, very rarely you should you need to cite your own work.
You do not have to cite a source if the information is "common knowledge." This means that the information is something that most people would know without having to look it up. For example, the statement "Albert Einstein developed the theory of special relativity" is common knowledge that an educated science student would know and would not need to be cited.
Plagiarism is the presentation of someone else’s work, words, images or ideas as one’s own. Examples of plagiarism include, but are not limited to, the following:
The instructor should clarify what constitutes plagiarism and correct citation within a given course.
- Excerpt from 2020-2021 NWC Student Handbook