What is the origin of acme?
Acme, “the highest point; summit; peak,” comes straight from Greek akmḗ “point, highest point, extremity.” Akmḗ is one of many Greek words derived from the widespread Proto-Indo-European root ak-, ok– “sharp, pointed, angular.” Other Greek derivatives include ákros “topmost, outermost,” as in akrópolis “upper city, citadel” (English acropolis), akrobátēs (English acrobat), literally “height walker,” and akís “point.” Latin derives from the same root ācer (stem ācr-) “sharp, stinging,” aciēs “point,” acidus “sour, acid,” and acūtus “sharp, sharpened” (English acute). The Proto-Germanic root from ak-, ok– is ag-. The Proto-Germanic noun agyō becomes ecg “sharpness, sharp side, blade, sword” in Old English (and edge in modern English); the Proto-Germanic verb agyan becomes eggja “to goad, incite” in Old Norse, the source of English egg (on). Acme entered English in the second half of the 16th century.