yellow

Old English geolu named the color of egg yolks and ripe wheat, but the word arrived from Proto-Germanic gelwaz, which traced back to a Proto-Indo-European root ghel- meaning to shine or gleam. That same root branched into words that appear wildly unrelated: Latin galbus (pale yellow), Greek chloros (green-yellow, from which chlorophyll derives), and Old English galla (bile, the yellow-green fluid of the liver). The biological and the luminous collapsed into a single sound at the earliest recoverable layer. Color perception and light perception were once the same act.

Proto-Germanic gelwaz gave rise not only to English yellow but to German gelb, Dutch geel, and Swedish gul. The Old Norse form gulr appears in 13th-century Eddic poems to describe sulfur and flame. Old English geolu became Middle English yelwe before settling into yellow by the 15th century, and scribes in the 14th century could spell it gelow, yelou, or yelewe depending on dialect. Chaucer used yelwe in the Knight's Tale around 1390, describing the gold-veined marble of a temple. The vowel was restless; the hue was not.

The PIE root ghel- also underlies English gold, glow, gleam, and glitter via a related Germanic branch. In Greek it produced chloros, initially meaning pale green, which entered Latin as chlorus and now lives in chemistry as chloro- in chlorophyll. The human eye is most sensitive to yellow-green light near 555 nanometers, and language appears to have recognized this perceptual primacy early. Proto-Indo-European communities named shining, gleaming, and yellow-green with the same sound cluster, because the naming followed the seeing.

By the Tudor period, yellow carried symbolic weight in English culture that had nothing to do with its etymology. Yellow was the color of jealousy in Renaissance drama and of cowardice in later slang, with yellow-bellied appearing in print by 1856. Newspapers like William Randolph Hearst's New York Journal earned the label yellow press in the 1890s for their sensational reporting. The word had long since left its ancient root of light and shine; it had become a color people used to say things that had nothing to do with color.