半はん群ぐんはんぐんMeanings1nounsemigroupmathematics›A mathematical term for a set equipped with an associative binary operation. Used in algebra and theoretical computer science.自し然ぜん数すう全ぜん体たいの集しゅう合ごうは、加か法ほうに関かんして半はん群ぐんをなす。