published means anything that appears in an academic journal, an in-house university journal, an article or a review in a teaching magazine, a chapter in a published book, or the author publishes a commercial book based on research etc.
Articles are either refereed or unrefereed, which means that if they are referreed they are submitted to a selection panel or an editorial committee before they are published. Unrefereed articles may be used when your university will print anything that is submitted to them.
Self-published materials where you pay the publishers and printing (e.g. a textbook) and sell or give away to a limited audience carry very little weight when calculating points and for articles put on your resume. An article in an international refereed journal carries more weight than a local refereed journal, which is worth more than an unrefereed article and so on.