A peer-reviewed or refereed journal is one in which the articles are subjected to an external review process. Specialists or scholars in the same discipline review a draft of the article to evaluate the quality of scholarship, clarity & soundness of the research & conclusions, its contribution to the field, etc. The reviewers might suggest modifications to the article prior to publication.
Scholarly academic journals are used to share the results of research with other researchers in that field of study. The articles typically include bibliographies with citations to sources. Not every scholarly journal makes use of the peer-review process, but many online databases treat the concepts as synonymous.
What is the difference between scholarly, trade and popular articles?
Okay, I understand what it is, but how does it work?
Check out this excellent video from North Carolina State University to learn more: