In dictionaries, cosmos is variously defined as ‘The universe regarded as an orderly, harmonious whole’, ‘An ordered, harmonious whole’, and ‘Harmony and order as distinct from chaos’. Pythagoras or his Pythagorean followers called the Universe Kosmos because he/they regarded the physical world as a ‘perfectly ordered and harmonious system’.
In Panosophy, Cosmos, with a capital C, has essentially the same meaning, except that Universe refers to the Totality of Existence, not just the physical universe of matter, space, and time, accessible to our five senses of sight, hearing, smell, taste, and touch.
Probably about 1200, from Latinized form of Greek kosmos ‘order, arrangement; decency, good behaviour; regularity, good government; world, universe; ornament decoration, finery; glory, honour’, of uncertain origin. Except for the use of cosmos in 1200, the word disappears from the record until 1848, in a translation of Alexander von Humboldt’s Kosmos.
The related verb kosmein meant generally ‘to dispose, prepare’, but especially ‘to order, arrange, and equip (troops for battle); to set (an army) in array’; ‘to establish (a government or regime), to rule, govern’; ‘to honour, extol’; and ‘to deck, adorn, dress’ (especially of women), a meaning we find in cosmetic, originally ‘the art of beautifying the body’.