gʰewd-yo-
“rejoicing, delight”joy, enjoy, rejoice, jewel
Extended form yielding Latin gaudium > Old French joie, English joy, enjoy, rejoice, jewel.
Discussion
The Proto-Indo-European root *gʰewd-, carrying the sense of rejoicing or taking delight, produced a yo-stem derivative *gʰewd-yo- that became one of the great emotional words of the Western tradition. Pokorny (IEW 453) reconstructs the base as *gāu-, *gəu- with meanings centering on rejoicing, and the evidence, though concentrated primarily in the Italic branch, is semantically rich and culturally far-reaching. Latin gaudēre, meaning "to rejoice, to be glad," is the central reflex, and from its past participle stem gavis- and the noun gaudium, meaning "joy, delight, gladness," flowed an extraordinary cascade of Romance and English vocabulary. Old French reshaped gaudium into joie, which English borrowed as joy in the thirteenth century, and from the same French line came enjoy, originally meaning to give joy to oneself, and rejoice, from Old French rejoir, to feel joy again. The Latin adjective jocālis, meaning "pertaining to play or jest," derived from the related noun jocus (joke, game), which shared the root's semantic field of delight and amusement, eventually produced Old French joel, yielding English jewel — literally a plaything, a pretty trifle, an object of delight. The progression from abstract rejoicing to a physical ornament of pleasure is a characteristically Roman semantic development, grounding the emotional in the material. Watkins notes the root's presence in the Latin compound gāvīsus, the irregular perfect participle of gaudēre, which preserves an archaic long vowel pointing to the original PIE ablaut pattern. The Germanic branch appears not to have preserved clear reflexes of this root, making it one of those cases where a PIE formation survived robustly in one branch while vanishing in others — yet through the enormous cultural prestige of Latin and French, the root's descendants became central to the English emotional vocabulary. That the same prehistoric root meaning "to rejoice" gave rise to both the abstract noun joy and the concrete noun jewel speaks to the deep human habit of naming our treasured objects after the feeling they provoke.