What is peer-review?
Peer-review refers to the rigorous process that articles undergo before they may be published. Other scholars in the author's field or discipline review and evaluate the article for quality and validity. If lacking, the article may be rejected, but otherwise, the article is accepted, often with suggestions for revision.
Peer-reviewed journal vs. scholarly journal articles
Not all scholarly journal articles are peer-reviewed. However, all peer-reviewed articles (aka refereed articles) are scholarly.