jupon UK /ˈd͡ʒu.pɒn/US /ˈd͡ʒu.pɑn/ noun2 •(historical) A close-fitting sleeveless jacket, descending below the hips, worn over armour.Some wore coat armour, imitating scale, And next their skins were stubborn shirts of mail; Some wore a breastplate and a light juppon, Their horses clothed with rich caparison — 1700 •A petticoat. formsjupons