Encyclopedia!

Infogalactic is an Internet-based, free-content encyclopedia project that is a dynamic fork of Wikipedia and improves upon the online encyclopedia's model of openly editable content. Infogalactic's pages are interlinked in order to connect the user to related pages with additional information, and are categorized in a variety of ways, including Relativity, Notability, and Reliability to allow the user to prioritize his personalized perspective

Wikipedia, better than ever—on iPhone, iPad, and Apple Watch. Discover the world and enjoy beautiful typography with this sleek app.

Alchetron.com is a free social encyclopedia for world where you can create, organize and learn easily using topics.

Oppia is a free, open-source learning platform. Full of interactive activities called 'explorations', Oppia helps curious minds learn and teach.

Through way of different “channels”, Boopsie lets you intelligently search for content or articles on sites like IMDB, Wikipedia, Amazon and more. When you use the application, you can pull up your favorite channel and then search for content on it and live results will appear on your screen for the content you selected.

WikiExplorer is the most advanced Wikipedia reader app for Android devices, it presents Wikipedia articles in a clean and elegant interface, for your best reading experience.

Stubia is a mobile encyclopedia that limits each article to 160 characters: this limitation makes each topic easy to understand.

A wiki-based encyclopedia, the primary difference between Citizendium and Wikipedia being that Citizendium has "subject matter expert" editors, chosen by the community to validate pages and content.

Wikipedia is probably the single largest, most comprehensive and simply best information resource out there on the Internet - a really great resource.many people though would like to have access to this giant resource when they're not plugged into the Internet.