非ひユークリッド幾き何か学がくひユークリッドきかがくMeanings1nounnon-Euclidean geometrymathematics›Technical term in mathematics referring to geometries where Euclid's parallel postulate does not hold, such as hyperbolic or elliptic geometry.非ひユークリッド幾き何か学がくは、平へい行