According to the dictionary definitions
Wiki is ‘a website or database developed collaboratively by a
community of users, allowing any user to add and edit content’ and the wiki
word is derived from the Hawaiian Phrase ‘wiki wiki’ which means quick.

taken from here
Wiki can be a great source for language classrooms. It
is used both for sourcing knowledge or modifying an information
collaboratively. For example, students as a class can crate a mini-encyclopaedia
by researching and posting about one topic assigned. They can also create
stories individually or in groups or create a dictionary.
It is also a good way for book projects. Students have
a chance to write reviews or edit or delete anything they wish on a page
created by the teacher. Here is the screenshot of my first wiki! I wrote a
review about one of my favourite books, 1984 and created a wiki entry on the
wiki page created by our instructor. Enjoy reading!