Help:What is a wiki
A Wiki is a collaborative website. What does that mean? Well that means all the content on the website can be edited or added to by everyone, hence the collaborative part.
And no, it has nothing to do with wookiees.
BTW (at least according to Wikipedia), Ward Cunningham coined the term wiki after the "wiki wiki" or "quick" shuttle buses at Honolulu Airport. Wiki wiki was the first Hawaiian term he learned on his first visit to the islands, when the airport counter agent directed him to take the wiki wiki bus between terminals. According to Cunningham, "I chose wiki-wiki as an alliterative substitute for 'quick' and thereby avoided naming this stuff quick-web."