What speakers mean by it now
Choice is one of the ordinary nouns of decision. It can name the act of picking among options, the freedom or power to pick, the option that was picked, or the field of options itself. As an adjective it marks something as especially good or preferred: ripe fruit sold as choice, a seat called choice because it is the one people want. In New Zealand slang it can even stand alone as a positive reaction, roughly equal to excellent. On the surface the word looks like a native partner of choose, chosen, and choosy.
The origin of the word choice is not that simple partnership. English inherited the verb. It borrowed the noun.
Borrowed beside a verb it already had
Middle English first records chois, also spelled choys, around 1300 for the act of selecting. Early in the fourteenth century the same form could mean the capacity to select. By the late fourteenth century it could mean the person or thing that had been selected. The immediate source is Old French chois, known from the twelfth century and continued in Modern French as choix.
French had formed that noun from the verb choisir. In Old French the verb covered choosing, distinguishing, discerning, recognizing, and perceiving. English did not take the verb. Old English already had ceosan, a strong verb meaning to select, seek out, test, taste, and approve, which became modern choose. What English imported was the French noun sitting beside a verb it already possessed.
The route of choisir into French is not fully settled. Sources agree that the verb is Germanic, matching Gothic kausjan, to test, taste, or choose, and a reconstructed Frankish verb of the same type. Both go back to Proto-Germanic *kauzijaną, a causative formation beside *keusaną, to choose or try. Some etymologies insert an unattested Vulgar Latin *causire as the step from Germanic into Romance. Others treat choisir as a direct Germanic loan into Gallo-Romance. The Latin form is a reconstruction, not a documented word.
The same root on two paths
Under the French loan and the native verb sits one Indo-European root, reconstructed as *geus- or *gews-, with a range that covers tasting and choosing. In Greek and Latin the family stayed close to the mouth: Greek geuesthai, to taste, and Latin gustare, to taste, later feeding English gusto, disgust, and gustatory. In Germanic and Celtic the sense more often shifted toward trying or selecting.
English had already built its own noun from that root. Old English cyre meant selection, free will, or election. It is a West Germanic formation of the same base that produced Dutch keur and German Kür. Early Middle English still shows kire and cure. Then the native noun disappeared.
The usual explanation is sound, not meaning. As English changed, cyre no longer resembled any living form of choose. Old French chois did. Speakers kept the inherited verb and replaced the inherited noun with a French word that seemed to belong to it. Historical dictionaries therefore treat the modern noun as only remotely related to choose: they share an ancestor, but choice did not grow inside English from the verb.
A late Old English adjective chis, meaning fastidious or particular and tied to ceosan, probably also colored the borrowed form. Middle English spellings later include choyse, choise, and choyce before choice became the standard.
How the senses moved
The earliest English uses stay close to French: an action, then a capacity, then the selected object. By the mid-fourteenth century the noun and a new adjective were feeding each other. As an adjective, choice meant fit to be picked, outstanding, or of high quality. From that sense the noun could also mean the pick of a group, the best part, still alive in phrases such as a choice cut.
Some older senses have dropped away. Writers once used the word for care and judgment in selecting, almost a synonym of discrimination. It could also mean a sufficient number to pick among. Those uses are obsolete. The modern noun is more about options and outcomes than about the skill of picking.
Later English added choiceness from the adjective. Informal choosy is a different formation, from choose plus a suffix, but it occupies the same neighborhood as the old native chis. In twentieth-century mathematics, choice also became a shorthand for the axiom of choice, a technical sense that still rests on the idea of selecting.
A noun English already had
If cyre had survived, it might have looked something like kire, a cousin of Dutch keur rather than a partner of choose. English did not need a French word for the idea of selecting. It needed a noun that still sounded like its own verb. The imported form won on resemblance.