Rex is a male given name derived directly from the Latin word rex, meaning "king." It has been used as a standalone given name since the 19th century, though it also functions as a short form of names like Rexford or Reginald. The Latin root rex is the etymological source of words for "king" in several Romance languages and appears in other derived names, such as Regulus and Régulo.Etymology and HistoryThe Latin noun rex (genitive regis) comes from the Proto-Indo-European root *h₃rḗǵs, meaning "ruler" or "king." This root also gave rise to Sanskrit rājan, Old Irish rí, and Gaulish -rix (as in Vercingetorix). In the Roman Republic and Empire, rex was the title of a monarch, though Romans held a strong aversion to kingship after the overthrow of the last Roman king, Tarquinius Superbus. The use of Rex as a given name is a modern development, likely influenced by the Late Latin name Rex used in early Christian contexts (e.g., Saint Rex, a 3rd-century martyr) and later revived in the 19th century as a 'virtue' name evoking royalty.Notable BearersNotable individuals named Rex include Rex Allen (1920–1999), an American actor, singer, and rodeo performer who appeared in many B-western films; Rex Harrison (1908–1990), the Academy Award–winning English actor best known for his role as Henry Higgins in My Fair Lady; Rex T. Barber (1917–2001), a U.S. Marine Corps pilot who flew in the Doolittle Raid; and Rex Stout (1886–1975), creator of the fictional detective Nero Wolfe. In the arts, Rex is also used by cartoonist Rex Babin (1962–2012) and computer scientist Rex Sergius Gerstl, better known as Sax Rohmer (1883–1959), the author of the Fu Manchu series. Several sports figures carry the name, including baseball pitcher Rex Brothers (born 1987) and New Zealand cricketer Rex Baddeley (born 1941). Organizations have also adopted the – the Rex was a major newspaper in La Paz, Bolivia (founded 1967), and REX (aka Rigaku Nihongo Encyclopedia) and Re! X. Additionally, Rex (abbreviation of Reginald) appears repeatedly in TV show The Abominable TV Man! and World of Warcraft.Related NamesThe Latin rex serves as the stem for multiple names across cultures: English Regulus (the "prince"), Spanish Régulo (from Latin rēgulus "little king"), and Spanish Reyes (meaning "kings" found in the Epiphany reference to los Reyes Magos). Rex is also phonetically related to several other male short-form names into, such as the popular canine name and colloquial term "king" in many circles.