noun, feminine/kɑ̃.bʁyʁ/plural: cambrures
cambrure is feminine in French.
instep, arch (of the foot); camber (of a road); small of the back
“Sa voix maintenant prenait des inflexions plus molles, sa taille aussi; quelque chose de subtil qui vous pénétrait se dégageait même des draperies de sa robe et de la cambrure de son pied.” — Her voice now took more mellow inflections, her figure also; something subtle and penetrating escaped even from the folds of her gown and from the line of her foot.
From cambrer + -ure.