Classical element to use the term "element (στοιχεῖον, "stoicheion")" in reference to air, fire, earth, and water. The ancient Greek word for element, "stoicheion" (from "stoicheo", "to line up") meant "smallest division (of a sun-dial), a syllable", as the composing unit of an alphabet it could denote a letter and the smallest unit from which a word is formed. A similar alphabetic metaphor may be the origin of the equivalent Latin word "elementum" (from which the English word comes), possibly based on the names of the letters 'l', 'm', and 'n', though the validity of this idea is debated. In his "On
Archaic humans of modern humans. Archaics are distinguished from anatomically modern humans by having a thick skull, prominent supraorbital ridges (brow ridges) and the lack of a prominent chin. Anatomically modern humans appear from over 160,000 years ago in Ethiopia and after 70,000 years ago (see Toba catastrophe theory), gradually supplanting the "archaic" human varieties. Non-modern varieties of "Homo" are certain to have survived until after 30,000 years ago, and perhaps until as recently as 10,000 years ago. Which of these, if any, are included under the term "archaic human" is a matter of definition and varies among authors. Nonetheless, according to