|Headquarters||Westbourne Studios, London|
What3words (stylized what3words) is a geocoding system for the communication of locations with a resolution of three metres. What3words encodes geographic coordinates into three dictionary words. For example, the torch of the Statue of Liberty is located at "toned.melt.ship". This differs from most other location encoding systems in that it displays three words rather than long strings of numbers or letters. What3words has a website, apps for iOS and Android, and an API that enables bidirectional conversion of what3words address and latitude/longitude coordinates. As the system relies on a fixed algorithm, not a large database of every location on earth, it works on devices with limited storage and no internet connection, and the encoding is permanently fixed and unchangeable.
Founded by Chris Sheldrick, Jack Waley-Cohen, Mohan Ganesalingam, and Michael Dent, what3words launched in July 2013. Sheldrick and Ganesalingam originally conceived the idea after Sheldrick struggled to get equipment and bands to event locations on time due to inadequate addressing while working as a concert organizer. The company was incorporated on March 5, 2013 and a patent application for the core technology filed on April 19, 2013.
In November 2013, what3words raised $500,000 of seed funding, and in March 2014 the company raised a second seed round of $1,000,000. On November 3, 2015, what3words closed a $3.5 million Series A funding round led by Intel Capital, with Li Ka-shing's Horizons Ventures participating. On June 29, 2016, what3words closed a $8.5 million Series B round led by Aramex. On January 10, 2018 Mercedes-Benz bought approximately 10% of the company, and announced it would be built into future vehicles . The A-Class (launch in May 2018) is the first vehicle in the world with what3words on board.
What3words uses a grid of the world made up of 57 trillion squares of 3 metres by 3 metres. Each square has been given a three-word English address. What3words has named the world's landmass with three words in various other languages. As of December 2016[update], what3words addresses (as well as web and iOS app user interface) are available in Arabic, Finnish, French, German, Italian, Mongolian, Polish, Portuguese, Russian, Spanish, Swedish, and Turkish; the iOS app also supports Swahili. What3words launched 12 more languages at the start of 2018: Indonesian, Zulu, Japanese, Korean, and Hindi. The company has also mentioned Chinese and various languages of India, including Bengali, Farsi and Urdu.
Each what3words language uses a wordlist of 25,000 words (40,000 in English, as it covers the sea as well as land). The lists go through multiple automated and human processes before being sorted by an algorithm that takes into account word length, distinctiveness, frequency, and ease of spelling and pronunciation. Homophones and variant spellings are treated to minimize any potential for confusion, and offensive words are removed.
The what3words algorithm actively shuffles similar-sounding three-word combinations around the world to enable both human and automated error-checking. The result is that if a three-word combination is entered slightly incorrectly and the result is still a valid what3words reference, the location will usually be so far away from the user's intended area that it will be immediately obvious to both a user and an intelligent error-checking system.
The what3words system uses a proprietary algorithm in combination with a limited database, meaning that the core technology is contained within a file around 10 MB in size. The database is used to assign more memorable words to locations in urban areas. What3words originally sold "OneWord" addresses, which were stored in a database for a yearly fee, but this feature has been canceled.
Supporters of open standards denounce the what3words system for being controlled by a private business and the software for being copyrighted and thus not freely usable. The fact that similar addresses are purposely far away from each other is also seen by some as a disadvantage.
- Mercedes-Benz – in-car voice navigation system
- Land Rover – off-road driving
- Splyt – e-hailing, ride-sharing and taxi apps
- Speedy Route – route planning optimization
- Mongol Rally – addressing electric car charging points between the UK and Mongolia 
Aid and humanitarian
- Red Cross – Disaster relief 
- Tropical Health – mosquito net tracking
- United Nations – disaster and humanitarian reporting app UN-ASIGN
- Philippine Red Cross – identifying disaster zones
- Next Future Transportation – autonomous modules
- Bikxie Pink – bike taxi service in Delhi for women
- Quiqup – on-demand logistics in London, UK
Navigation and transit
- Navmii – offline navigation app
- Pocket Earth – offline navigation app
- RioGo – multimodal transit app for Rio Olympics
- TripGo – multimodal transit app
Delivery & logistics
- Aramex – global delivery and logistics 
- Deliver Addis – Ethiopian food delivery company
- Ivory Coast uses this system for mail deliveries.
- GoPato – drone delivery in Costa Rica
- Onibag – California-based bike courier service
- Mongol Post adopted what3words for postal deliveries throughout the country.
- Carteiro Amigo – parcel and post delivery in the favelas of Brazil
- Parcelly - Click and Collect Logistics.
Festivals and events
- in2care – mosquito trap maintenance in Tanzania
- Metcom – fire hydrant management in Colorado
- Pollinate – energy solar lighting installation in the slums of India
- Videre – solar lighting installations in Botswana
- Grand Prix for Innovation at the Cannes Lions International Festival of Creativity
- The Tech Awards Sobrato Organization Economic Development Award
- D&AD Black Pencil
- FT/IFC Transformational Business Awards commendation for Achievement in Transformational Technology
- KPMG Best British Mobile Startup
- PWC Great Innovation Challenge Winner
- Accenture Consumer Innovation Award
- BT Tech for Good Award
A number of parody sites have been created to satirize what3word's proprietary nature, including:
Alphanumeric competitors include:
- Open Location Code (2014)
- Makaney Code (2011)
- Geohash (2008)
- MapCode (2008)
- Universal Transverse Mercator coordinate system
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- "Location Pinpointing Startup what3words Adds $1M More To Its Seed To Flog More Map Labels". TechCrunch. AOL.
- "what3words closes $1m to expand 'alternative to postcodes' mapping service". Startups.co.uk: Starting a business advice and business ideas.
- "What3words adds $1M more to seed round". Venture Capital Post.
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- Lomas, Natasha (8 Jul 2013). "Location-Pinpointing Startup what3words Sells 10,000+ OneWord Map-Pins In First Week". TechCrunch.
- "what3words on Twitter: "we did charge for that functionality but no longer offer it."". 1 May 2015.
- "The best navigation idea I've seen since the Tube map". The Spectator. 25 October 2014.
- Crannell, C. W.; Parrish, J. M. (1957). "A comparison of immediate memory span for digits, letters, and words". The Journal of Psychology: Interdisciplinary and Applied. 44: 319–327.
- "What3Words is quite a find". The Boston Globe. 1 Jul 2016.
- Dodds, Leigh (14 Jun 2016). "What 3 Words? Jog on mate!".
- "What3words". OpenStreetMap wiki. 20 Jan 2017.
- "UN disaster app includes three word addresses". EE Publishers.
- Miles, Stuart. "Navmii navigation app turns driving into a game, uses What3Words to make sure you never get lost again". pocket-lint.com.
- "Ivory Coast post office adopts three-word system". BBC. 2016-12-09.
- "Mongol Post adopts what3words as national addressing system". Mongol Post. 23 May 2016. Retrieved 19 June 2016.
- "To Address Poverty, We Need Addresses". The Huffington Post UK.
- "Partner: In2Care Mosquito Traps & what3words". what3words.
- "Partner: Pollinate Energy Indian Slum Solar Lighting & what3words". what3words.
- Diaz, Ann-Christine (26 June 2015). "What3Words Innovation Grand Prix Cannes – Special: Cannes Lions – Advertising Age". adage.com.