To be brief, a scholarly article is one that is written by experts in the field, for other experts in that field.
Determining whether an article is scholarly or not takes work- you have to review the article and look for key indicators:
Some other differences between scholarly and popular articles:
NOTE: Books reviews and letters to the editor are generally not considered scholarly articles, even when they are published in a scholarly journal. Make sure you are not using a short book review or letter as a scholarly journal.