An Etymological Dictionary of Astronomy and Astrophysics

1a) General: A condition or place of great disorder or confusion.

1b) Math., Physics: Highly disordered evolution of some → dynamical systems
which is sensitively dependent on → initial conditions. In a → chaotic system
the → aperiodic, → nonlinear evolution grows → exponentially with time. Ordinary chaos is not → turbulence, but turbulence is always chaotic.

2. In → astrogeology, a distinctive area of fractured terrain on a planet or satellite, e.g. Gorgonum Chaos located in the southern hemisphere of Mars.

Etymology (EN): Chaos, in Gk. mythology and cosmology, the void existing at the beginning of the creation, as evoked in Hesiod’s (c. 850 B.C.) Theogony. However, the meaning of chaos, used by Hesiod, is a matter of debate. Some have interpreted it as the primeval absence of order (hence → confusion). Subsequently, the Roman writer Ovid (43 BC-17? AD) described Chaos in his Metamorphoses as an unordered and formless primordial mass, and opposed Chaos to Cosmos “the ordered universe.”

Chaos “gaping void,” from L. chaos, from Gk. khaos “abyss, that which gapes wide open, is vast and empty,” from *khnwos, from PIE base *gheu-, *gh(e)i- “to gape.”

Etymology (PE): 1) Varšun, from Tabari varâšun, Gilaki varâšin, daršin, uršin all meaning “confused, unordered, untidy,” cf. Qomi šur-o-šin “chaos, confusion”. The stem šun-/šin- is related to Mod.Pers. šân- in afšândan, šândan “to disperse, scatter, stew” (Mid.Pers. afšândan “to spread, scatter”), Gilaki šondan “to disperse,” Hamadani šuândan “to derange, disorder,” Laki veršânâ “to disperse, scatter,” Šuštari šayn “to shake, agitate,” Kermâni owšin “a winnowing fork to separate chaff from the grain,”
Laki šovâné “scattered household furniture,” Tabari timšan “sowing seeds;” all ultimately from Proto-Ir. *šan- “to shake;” see also → confuse. The prefix var-, variant bar- “up, over” (as well as dar- “in”), denotes “disorder, confusion” as in darham barham “upside-down, helter-skelter”.

2. Šivâr “depression between two terrains,” from Tabari; probably a variant of šiyâr, → groove.