Scholarly sources are:
We usually talk about scholarly articles, but there are also scholarly books called monographs. These are published by university presses and have many of the same identifying characteristics as scholarly articles.
There are certain characteristics that make it easy to recognize a scholarly article when you see one.
To view the basic components of a scholarly article, explore this brief, visual tutorial: Anatomy of a Scholarly Article
Peer review is the most rigorous form of quality control that exists for scholarly information sources. An expert could write a webpage or magazine article - even one intended to be read by other experts - but it would still not be considered scholarly, because the quality control process for vetting the information before it is published is not rigorous enough.
This video below, from NCSU, does a great job of explaining how the peer review process works.
Double-blind peer review is considered the strongest method of review because, in theory, the author does not know who the reviewers are and the reviewers do not know who the author is. This is intended to reduce bias. In practice, scholars working in the same subject area usually know each other and can recognize each others' specializations and writing styles. In double-blind peer review, though, the reviewers are volunteers who do not work for the journal.
Editorial review involves reviewers who are members of the journal's editorial board, instead of anonymous volunteer experts as in peer review. It is still a very strong method, and editorially reviewed articles are still considered scholarly.
Some library databases contain scholarly articles, exclusively. Others contain a mix of scholarly and non-scholarly sources. If you are searching a databases that mixes scholarly and non-scholarly content, or if you are using OneSearch, there is a way to ensure that all your search results will come from scholarly sources. You will find this feature on the Advanced Search screen and adjacent to the Search Results list.
If you are using OneSearch, view the column to the left of your Search Results list. You will see a check box for Scholarly (Peer Reviewed) Journals. Click it and then click the Update button that appears, and that will eliminate all results from non-scholarly publications. Most databases work similarly.
Note: Not all items published in scholarly publications are scholarly articles; some scholarly publications include items like book reviews and editorials which would not be considered scholarly.
Sometimes it is appropriate to use non-scholarly information sources.
Some research areas do not produce scholarly journals. These include fields like fire fighting, sound equipment sales, hotel management, etc., which produce trade journals or professional journals, instead. Trade and professional journals are: