A publication is considered to be scholarly if:
It is authored by academics for a target audience that is mainly academic.
The printed format tends isn't a glossy magazine.
It is published by a recognized society with academic goals and missions.
A publication is considered to be peer reviewed if:
Its articles go through an official editorial process that involves review and approval by the author's peers (people who are experts in the same subject area.)
Most (but not all) scholarly publications are peer reviewed. Some trade publications are actually peer reviewed, but ProQuest does not consider them when filtering on peer reviewed. This is because getting results from trade publications instead of academic journals can be frustrating to researchers. Instead, ProQuest excludes these peer reviewed trade publications and only considers publications that are scholarly in terms of content, intent, and audience.