What3words

What3words (stylized as what3words) is a proprietary geocode system designed to identify any location on the surface of Earth with a resolution of approximately 3 metres (9.8 ft). It is owned by What3words Limited, based in London, England. The system encodes geographic coordinates into three permanently fixed dictionary words. For example, the front door of 10 Downing Street in London is identified by ///slurs.this.shark. What3words differs from most location encoding systems in that it uses words rather than strings of numbers or letters, and the pattern of this mapping is not obvious; the algorithm mapping locations to words is copyrighted. What3words has been subject to a number of criticisms both for its closed source code and the significant risk of ambiguity and confusion in its three word addresses. This has led rescuers to advise against the use of What3words in safety critical applications. The company has a website, apps for iOS and Android, and an API for bidirectional conversion between What3words addresses and latitude–longitude coordinates.