Peer-reviewed articles are generally externally reviewed articles which are reviewed under either a blind review system (where the reviewers don't know the identity of the author of a manuscript) or less commonly a double-blind system (where neither the journal editors nor the reviewers know the identity of the authors of a manuscript). This is also what is commonly meant by a journal being a refereed journal. Matters related to citation indexes are separate and distinct.
To answer simply: terminology-wise, peer-reviewed and referred journal are more or less the same, but the peer-reviewing process differs according to different journals. A common rating system is "indexing", for example, the most commonly used index worldwide is science citation indexed (SCI) or social science citation index (SSCI) or engineering index (EI), if a journal is indexed by there three, it's a repute journal recognized by the international community. Also another key indicator is the "impact factor" (IF), for the same indexed journals by SCI, the bigger IF is has, the more citations it receives, the more influence it suggests. To give you an example, in APU, we have RCAPS journal, or for linguistics Polyglossia (if my memory is correct), RCAPS journal is blindly reviewed by APU professors, however, it is a low-end journal, no major indexing what so ever. Another peer-review journal of APU is called Asia Pacific World, it actually has a review board of international experts, but not indexed by the major three, thus it is a normal peer-reviewed journal. (with low impact), as for Polyglossia... no comment.
Refer to this link for a further look: https://en.wikipedia.org/wiki/Science_Citation_Index
So the SCI, SSCI, and EI are what separate developed journals from those that are developing, then. I am going to test out Scopus, CiteSeer, and Google Scholar to see if these provide information for non-SCI/SSCI indexed articles. Things like blind review, whether a journal is reviewed externally or internally, and whether authorship is limited to internal organization members also shed light on the level a journal might be in its objectivity.
Peer-reviewed articles are generally externally reviewed articles which are reviewed under either a blind review system (where the reviewers don't know the identity of the author of a manuscript) or less commonly a double-blind system (where neither the journal editors nor the reviewers know the identity of the authors of a manuscript). This is also what is commonly meant by a journal being a refereed journal. Matters related to citation indexes are separate and distinct.
Terminological differences. People do understand the meaning of both peer-reviewed and referred. What confuses them is, in some cases it is written and asked for peer-reviewed in others referred. Both have connotationally synonymous. It is matter of preferences in use. So journals use either of it. Don't expect both the terms to be written in a journal. But in India , may be in other countries, journals started writing both 'peer-reviewed and refereed quarterly journal' just to owe the contributors for getting the academic score for promotional benefits.