Wikipedia is a free, multilingual, open content encyclopedia project operated by the United States-based non-profit Wikimedia Foundation. Its name is a portmanteau of the words wiki (a technology for creating collaborative websites) and encyclopedia.
The Encyclopedia of Life (EOL) is a collaborative project to organize and make available via the Internet virtually all information about life present on Earth. The EOL staff is made up of scientists and non-scientists working from museums and research institutions around the world.
Medpedia is a collaborative project (or collaborative medical encyclopedia project) for sharing and advancing medical knowledge among medical professionals and the general public.
The Internet Encyclopedia of Science is an online science encyclopedia that has the goal to provide a comprehensive source of information covering all aspects of contemporary science, mathematics, and technology.
TechWeb’s TechEncyclopedia offers definitions and links for more than 20000 information technology terms. It shows 10 terms similar to the typed entry – 5 entries before the entry and 5 entries after the entry.
The Library of Economics and Liberty is dedicated to advancing the study of economics, markets, and liberty. The Concise Encyclopedia of Economics (CEE), which is contained in it, provides a wealth of economic analysis about important issues in a comprehensive, yet readable and engaging format.
Uncyclopedia is “the content-free encyclopedia that anyone can edit”. It is formatted as a parody of Wikipedia and aims ultimately to parody all encyclopedic subjects. Read it for fun.