Someone who is asked to review the work done by someone else, and who comes from the same background as the author. For example, one climate scientist reviewing a study done by another climate scientist to see if it is objective and scientifically sound. Or one programmer looking at the code written by another programmer to see if it can be improved.
No, not all journals are peer-reviewed. Peer-reviewed journals have articles that are reviewed by experts in the field before they are published, but there are also non-peer-reviewed journals that do not have this review process.
Yes, the book has been peer-reviewed.
No, the content on Academia.edu is not peer-reviewed.
It is best to assume that no website is peer-reviewed.
Yes, the articles on ResearchGate are not peer-reviewed.
Yes, the journal Science is peer-reviewed.
Yes, the source in EBSCO is peer-reviewed.
Yes, Sage Journals are peer-reviewed.
No, not all journal articles are peer reviewed.
No, the content published on arXiv is not peer-reviewed.
No, the research published on bioRxiv is not peer reviewed.
Yes, "American Scientist" is a peer-reviewed journal.