A peer-reviewed journal is a special type of journal. Peer reviewed (or refereed) journals have been reviewed by a panel of subject experts, a researchers "peers". These peer reviewers scrutinize articles for significance, relevance, sound research design, accurate presentation, and clarity before they are accepted for publication.
Many databases provide the feature that allows searches to be limited to peer-reviewed journals. Look for a limit box to check for peer-reviewed or refereed. But if you still aren't sure, use Ulrich's Directory to look up whether a journal is peer-reviewed or not.