Urban Dictionary

Urban Dictionary is a crowdsourced online dictionary of slang words and phrases that was founded in 1999 as a parody of Dictionary.com and Vocabulary.com by then-college freshman Aaron Peckham.

Some of the definitions on the website can be found as early as 1999, however most early definitions are from 2003. At the start of 2014, the dictionary featured over seven million definitions, while 2,000 new daily entries were being added. In November 2014, the Advertise page of the website states that, on a monthly basis, Urban Dictionary averages 72 million impressions and 18 million unique readers.

Anyone with either a Facebook or Gmail account can make a submission to the dictionary, and it is claimed that all entries are reviewed by volunteers. Site visitors may agree/disagree with definitions by an up/down vote system.

You can also download the app on App Store, Google Play and Windows Phone.

Source: en.wikipedia.org/wiki/Urban_Dictionary