Peer review is defined as obtaining advice on individual manuscripts from reviewers expert in the field who are not part of the editorial staff. Grant proposals, preprints, journal articles, data, books and conference submissions may all be subjects of peer review, with the goal of building trust in the validity, accuracy, quality and originality of the work.
A peer reviewed or peer refereed journal or article is one in which is subjected to this advice.
Note the Author's credentials, abstract, and citations in the text. These features indicate that the article is scholarly.
Scholarly articles often have abstracts, footnotes or citations, and list the author's credentials.
Popular articles, like this one from Scientific American may be from a reputable publication but not peer-reviewed.
The Author may or may not be an academic, but the article is written for a popular audience.
There are may be no footnotes or citations, and often include colorful pictures.
