Making something pure or better by removing unwanted parts; also improving something through careful adjustment or education.
From Old French 'refiner' (re- meaning again + finer meaning to finish). Originally used for purifying metals and oils through chemical processes, the sense expanded to mean improving ideas, manners, and skills.
Oil refineries literally separate crude oil into useful products, and that industrial process gave us the word for 'refining your skills' or 'having refined taste'—the same chemical principle of separating the valuable from the worthless applies to learning and culture.
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