Origins
The word 'universe' embodies a philosophical proposition in its very structure.βββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββββ It derives from Latin 'Ε«niversum,' the neuter form of the adjective 'Ε«niversus,' meaning 'all together,' 'whole,' or 'entire.' This adjective is a compound of 'Ε«nus' (one) and 'versus' (turned), the past participle of 'vertere' (to turn), from the PIE root *wert- (to turn). The literal meaning of 'Ε«niversum' is thus 'turned into one' or 'combined into a whole' β a word that encodes the idea that the staggering diversity of existence has been gathered, rotated, and fused into a single, unified totality.
The Latin 'Ε«niversum' was used by Cicero, Lucretius, and other Roman writers to denote 'the whole world' or 'all things taken together.' It entered Old French as 'univers' and passed into English around 1340. For most of its history in English, 'universe' meant 'everything that exists' in a general philosophical sense. The modern cosmological meaning β the totality of space, time, matter, and energy governed by physical laws β became standard only with the development of scientific cosmology in the twentieth century.
The PIE root *wert- (to turn) is one of the most prolific in the English vocabulary, and the family of words it produced through Latin 'vertere' (to turn) is breathtaking in its range. 'Verse' comes from Latin 'versus' (a turning, a furrow, a line of writing), because writing was metaphorically conceived as plowing: you reach the end of one line and 'turn' to begin the next, just as a farmer turns the plow at the end of a furrow. 'Reverse' is 'to turn back.' 'Diverse' is 'turned apart' (from 'di-' + 'vertere'). 'Controversy' is 'a turning against' (from 'contra-' + 'versus'). 'Version' is 'a turning' of a text into another language. 'Vertebra' is a 'turning joint.' 'Vertigo' is the sensation of 'turning.' And 'university' β from Latin 'Ε«niversitas' β originally meant 'the whole,' 'the totality,' or 'a corporate body,' applied to the medieval guilds of masters and students that constituted the first European universities. A university, like a universe, is diversity turned into one.
Later History
The cosmological concept encoded in 'universe' has expanded dramatically since the word entered English. In the medieval period, the 'universe' was a finite, geocentric system of nested crystalline spheres, with the Earth at the center and the fixed stars on the outermost sphere. The Copernican revolution displaced the Earth from the center. Galileo and Newton expanded the universe to encompass the solar system governed by gravitational mechanics. William Herschel and others in the eighteenth and nineteenth centuries revealed that the Milky Way was a vast system of stars. Edwin Hubble's observations in the 1920s demonstrated that the Milky Way was merely one galaxy among billions, and that the universe was expanding.
Today the observable universe is estimated to contain roughly two trillion galaxies spanning 93 billion light-years. The question of whether the total universe extends beyond the observable horizon β and whether there might be multiple universes (a 'multiverse') β remains at the frontier of cosmology. The word 'multiverse,' combining Latin 'multus' (many) with 'Ε«niversum,' is a deliberate etymological paradox: many things each turned into one. If the universe is everything turned into one, a multiverse is the proposition that there is more than one 'everything' β a concept that would have delighted and baffled the Roman philosophers who first gave 'Ε«niversum' its meaning.