A wiki is a web site designed to be extremely easy to edit.

The original wiki is at http://c2.com/cgi/wiki. Nowadays there are many more wikis. Wikipedia is only one example of a wiki, and not a very typical one, but it’s much better known than the others, so some people think “wiki” is short for “Wikipedia”.

See http://c2.com/cgi/wiki?WikiDesignPrinciples for Ward Cunningham’s original ideas about what a wiki should be like.

See http://en.wikipedia.org/wiki/Wiki for more definitions.