From North Carolina State University Library (Closed Captioned)
"Scholarly" sources are
Written by experts (majority have advanced degrees),
Contain original research,
Cite other sources extensively throughout their work and contain works cited section
Peer reviewed articles are scholarly articles that have undergone a review process by other experts in the field before being published (hence - reviewed by their peers).
“Popular” sources are
magazines, newspapers, books, websites, Youtube, trade journals etc.,.
written or produced for a general audience and informal in tone and scope.
reviewed by an editor but rarely cite other sources,
not peer reviewed
Scholarly (peer reviewed) Sources vs Popular Sources (In depth)