Wikipedia (wiki + encyclopaedia) is a multilingual, web-based encyclopaedia with free content.It is a wiki, which means Dial Probe Thermometers it is written by numerous volunteers, and most articles can be changed by anyone with Internet access and an adequate web browser.The project was started on January WAND 15, 2001.Wikipedia currently has more than 3 700 000 articles in many languages (including a million articles in English).