ARCHE'US, noun [Gr. beginning, or a chief.] A term used by the ancient chimists, to denote the interal efficient cause of all things; the anima mundi or plastic power of the old philosophers; the power that presides over the animal economy, or the vis medicatrix; the active principle of the material world. In medicine, good health, or ancient practice.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI