reles

Old French reles (also relaisse) came from relaissier, 'to leave behind,' which descended from Latin relaxare, 'to loosen, release.' The original sense was about a remainder or aftereffect — specifically the taste that lingered after a bite, the flavor that stayed when the food was gone. Relish was what was left behind.

English borrowed reles as 'relish' in the 1530s, and the word carried its two-faced nature from the start. There was the concrete sense — a condiment, something you add to food for flavor — and the abstract sense: the lingering enjoyment of an experience. To eat with relish was to savor the aftertaste of pleasure.

By the 1700s, relish-as-condiment had solidified in English. Pickled vegetables, chutneys, and sharp accompaniments were relishes. The word had circled back: from leftover taste to enjoyment to a physical substance designed to leave a leftover taste. The etymology ate its own tail.

American English gave relish its most familiar form: the chopped pickle condiment that goes on hot dogs. This bright green mixture, arriving at Fourth of July cookouts in glass jars, is the unlikely heir of a medieval French word for 'what remains.' The remainder became the main attraction.