Use authoritative dictionaries and reference sources.
Wikipedia might be a handy tool in some cases, but it's not what your professors would call a reliable or authoritative reference source. The library resources listed below provide access to scholarly information on a range of subjects. See the Library Research Guides to find many more.
Learning how to interpret citations you find in scholarly books and articles is a critical research skill and essential to efficiently finding the material you need for your assignments. Watch this video to learn how.