A Chinese word, signifying age or period, generally applied to the ten periods preceding the first Imperial dynasty, founded B.C. 2205. It extended over some 300,000 years. The first was founded by Puon-ku (highest eternity), and the last by Of-hi, surnamed Tien-Tse (son of heaven).
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894