elementary (adj.)

c. 1300, "earth, air, fire, or water; one of the four things regarded by the ancients as the constituents of all things," from Old French element (10c.), from Latin elementum "rudiment, first principle, matter in its most basic form" (translating Greek stoikheion), origin and original sense unknown. Meaning "simplest component of a complex substance" is late 14c. Modern sense in chemistry is from 1813, but is not essentially different from the ancient one. Meaning "proper or natural environment of anything" is from 1590s, from the old notion that each class of living beings had its natural abode in one of the four elements. Elements "atmospheric force" is 1550s.