Journals are where important research in a field is published. Journals come out a few times a year and include articles and reviews written by top scholars in a field. It is very competitive to get work published in a journal. A single journal subscription can cost hundreds and even thousands of dollars a year for a subscription here at UT.
When folks use the term, scholarly, they typically mean articles published in these journals, which are peer reviewed (or refereed). The peer review process is what makes publishing in these journals competitive: it's a long and rigorous vetting process wherein experts review the work of other experts.