Wikipedia is a free online encyclopedia created and edited by volunteers around the world and hosted by the Wikimedia Foundation, a nonprofit organization. It provides articles in hundreds of languages, covering a broad range of subjects and offering readers free access to shared knowledge. Visitors can search and browse articles, save favorites, and use the official Wikipedia mobile app to read offline, sync reading lists across devices, and customize their experience.

The Wikimedia Foundation also hosts a family of free knowledge projects. These include Wikimedia Commons, a media collection; Wikivoyage, a travel guide; Wiktionary, a dictionary; Wikibooks, a textbook library; Wikidata, a knowledge base; Wikiversity, learning resources; Wikiquote, a collection of quotations; Wikisource, a library of free-content texts; Wikispecies, a species directory; and Wikifunctions, a function library. The foundation supports MediaWiki, free, open wiki software, and Meta-Wiki, which provides community coordination and documentation. Wikipedia’s content is available under the Creative Commons Attribution-ShareAlike License, supporting reuse and collaboration.