The Collaborative International Dictionary of English (CIDE) was derived from the 1913 Webster's Dictionary and has been supplemented with some of the definitions from WordNet. It is being proof-read and supplemented by volunteers from around the world.
This electronic dictionary is also made available as a potential starting point for development of a modern comprehensive encyclopedic dictionary, to be accessible freely on the Internet, and developed by the efforts of all individuals willing to help build a large and freely available knowledge base.[1]
There are several derivative versions of this dictionary on the Internet, in some cases reformatted or provided with an interface: