Five primary criteria to consider when evaluating any kind of information, including web sites:
CARS: Credibility, Accuracy, Reasonability, Support
All of these resources specify the audience or type of publication. There is some overlap. The critical aspect is the intended audience, which is spelled out here and, sometimes, on a publication itself.
Different publications that evaluate the content and audience of journals, magazines, serials, etc., will use their own definitions. The following are not exhaustive. If you are viewing print publications, the distinctions are easier to define visually. In print, as a rule of thumb, pretty pictures, ads and other items that might detract from the content of an article are good indicators that the journal/serial/magazine is not academic.
Scholarly or academic journals (often conflated with peer-reviewed, or refereed journals)
Scholarly journals have an academic or "scholarly" audience, which includes researchers among others. Rarely, these are referred to as magazines. Peer-reviewed or refereed articles (with the exception of book reviews and editorials) are a subset of scholarly (or academic) journals and are reviewed by those schooled in the same discipline as its stated audience. Peer-reviewed articles are checked over for methodology, accuracy, and how they may contribute to or be of interest to the field. These types of journals are generally created around disciplines or "communities of practice". Most authors and reviewers have significant education and training in that discipline (typically years). Articles should have references and be of a minimum length (usually 8 or more pages). An example of a scholarly, but not peer-reviewed journal is Phi Delta Kappan. An example of a scholarly, peer-reviewed journal is Psychological Bulletin.
Articles are geared toward those in the business/industry of a particular field or discipline. This type of publication straddles the line between academic and popular. It may contain articles that are scholarly or that are of a practical nature. You may find policy/policies and statistics not found in other types of publications. Industry newsletters and bulletins are often considered trade publications. A few trade publications are peer-reviewed. Articles typically have no references and are shorter in length than academic journals. One example of a trade journal might be Journal of Advertising Research.
News or general interest
Articles are geared toward the public, are typically quite short (500 words or fewer), and contain no references. Written by journalists who may, or may not, have a degree or background in the subject area. An example might include the Los Angeles Times. These publications usually include terms like "news," "today," or "times" in the title.
Popular (aka consumer)
Articles are targeted at the public or an audience with a sustained interest in the topic and will vary in length. Usually, there are no references. Also referred to as a "consumer" journal or magazine. This type of publication shares some of the same attributes of news or general interest materials. The typical example used is Psychology Today.