Depending on the field, assignment and professor, you may be asked to find peer reviewed, refereed, academic, or scholarly articles. If you're confused about assignment requirements, we strongly encourage you to discuss them with your professor!
These terms are interchangeable and mean that the articles are always either reviewed or refereed by multiple experts (peers) in a highly structured and critical process. The author generally receives feedback from the reviewers, makes any required changes and resubmits the work, and then the journal editor decides whether or not to publish it.
These terms are interchangeable and mean that these articles are not always peer reviewed/refereed. These articles are still research focused and heavily sourced (lots of references), and written for an academic audience, but they may have only been reviewed by an editorial board, rather than content experts.