Wikipedia is a multilingual, web-based, free encyclopedia. It is a collaborative, cooperative effort by volunteer writers to provide up-to-date information on any subject imaginable.
Wikipedia is one of the most popular reference websites online, with millions of visitors every month. There are more than 19 million articles and 82,000 active contributors.
It is the #5 most popular website in the world coming after Google, YouTube, Facebook, and Baidu (Chinese search engine).
An encyclopedia is a reference tool. It may be general or subject-specific. The most important role is to provide an introduction to a subject. Encyclopedias are perfect for preliminary research. They may provide terms to help with further searching, names of people associated with the topic, and overview and context of the subject, or sometimes information about controversies.
Good encyclopedias are generally well-accepted information. They attempt to be neutral is how they present information. As such, they are good for report writing in elementary school. But for college-level research, more analytical or theoretical information is eventually required. An encyclopedia may lead you to that material, however.
Wikipedia is guided by the following principles, referred to as the Five Pillars:
Wikipedia Users Report from the Pew Research Center
Does Wikipedia Have An Accuracy Problem? The Atlantic