These databases are either links to scanned print journal articles in PDF/HTML or actual reference content on a website. For example, JSTOR has PDFs of past journal articles scanned and ready to read from the comfort of your dorm room. Grove Online is the actual multi-volume set recreated in a web format so it's like a scholarly website for music junkies! We still call Grove items "articles", but they are not journal articles.
Don't know which database you want? Go straight to the TCU Music database listing!