gʰelh₃-
“to shine, yellow, green, gold”yellow-green
Root for shining/yellow/green colors. Gives English "yellow", "gold", "glow", "green", Latin helvus.
Discussion
The root *gʰelh₃- ("to shine, to be yellow or green, gold") is treated in Pokorny (IEW 429–434) and reconstructed with a final laryngeal *h₃ based on the o-colouring visible in certain derivatives. This is one of the primary PIE colour roots, covering the yellow-green-gold spectrum—a range that many ancient languages did not subdivide as modern English does.
Greek khlōrós (χλωρός, "green, yellow-green, pale") preserves the root with *gʰ > kh and *l̥h₃ > lō. From this comes English chlorine (named for its yellow-green colour), chlorophyll ("green leaf"), and chloroform. The name Chloe (Χλόη, "green shoot, blooming") is a related derivative. Greek khólē (χολή, "bile, gall") belongs to the same family, bile being yellow-green; from it come English cholera, choler, melancholy ("black bile"), and cholesterol.
Latin helvus ("honey-yellow") may reflect a form of this root, and fel, fellis ("gall, bile") is a direct cognate of Greek kholḗ. The English word gall ("bile, bitterness") comes from Old English galla, from the same root via Germanic *gallōn.
In Germanic, Old English geolu ("yellow") directly continues the root with Grimm's Law reflexes (*gʰ > g), giving Modern English yellow. Old High German gelo and Old Norse gulr are cognates. Gold (Old English gold) likely derives from the same root, as the metal named for its yellow colour—*gʰl̥h₃-tó- ("the shining/yellow thing"). The word gleam may also be related.
Lithuanian geltonas ("yellow") and žãlias ("green") preserve both colour senses in a single language, illustrating the original breadth of the root. Old Church Slavonic zelenъ ("green") and žlъtъ ("yellow") show the same split.
The root's coverage of both yellow and green is typologically significant: Berlin and Kay's colour-term universals predict that languages at an early stage merge yellow and green under a single term, exactly what *gʰelh₃- represents.
Notes
Color distinctions between yellow/green were fluid in PIE