LOS, or Los, or LoS may refer to:

Science and technology

* Length of stay, the duration of a single episode of hospitalisation * Level of service (transportation), Level of service, a measure used by traffic engineers * Level of significance, a measure of statistical significance * Line-of-sight (disambiguation) * LineageOS, a free and open-source operating system for smartphones and tablet computers * Loss of signal ** Fading **End of pass (spaceflight) * Loss of significance, undesirable effect in calculations using floating-point arithmetic

Medicine and biology

* Lipooligosaccharide, a bacterial lipopolysaccharide with a low-molecular-weight * Lower esophageal sphincter, Lower oesophageal sphincter

Arts and entertainment

* ''The Land of Stories'', a series of children's novels by Chris Colfer * Los, or the Crimson King, a character in Stephen King's novels * Los (band), a British indie rock band from 2008 to 2011 * Los (Blake), a character in William Blake's poetry * Los (rapper) (born 1982), stage name of American rapper Carlos Coleman * "Los", a song from the Rammstein album ''Reise, Reise'' *Los, or 'Legion of Skanks', is a comedy podcast on Gas Digital Network.

Games and sports

* Line of scrimmage, in American football * Lucas Oil Stadium, Indianapolis, Indiana, the home of the Indianapolis Colts football team

Locations

* Îles de Los, Guinea * Los, Sweden * Łoś, Masovian Voivodeship, Poland * Los, a small List of craters on Mars#L, crater on Mars

Business

* LOS AS, a Norwegian electricity supplier and subsidiary of Agder Energi

Weapons

* PZL.37 Łoś, Polish bomber aircraft * Los (hunting rifle), Los (''Лось''), Soviet hunting rifle

Other uses

*Los (surname) * Law of the sea * London Oratory School, a Catholic secondary school in Fulham, London; commonly known as The Oratory * League of the South, a neo-Confederate group * los, ISO 639 code for the Loniu language of Papua New Guinea * ''los'', a Spanish determiners, determiner in the Spanish language * ''los'', a Spanish pronouns, pronoun in the Spanish language * LOS, the IATA code for Murtala Muhammed International Airport in Lagos, Nigeria * LOS, the National Rail code for Lostwithiel railway station in Cornwall, UK