群ぐん論ろんぐんろんMeanings1noungroup theorymathematicsA branch of abstract algebra that studies algebraic structures known as groups.群ぐん論ろんは数すう学がくの一いち分ぶん野やで、対たい称しょう性せいを扱あつかう。Group theory is a branch of mathematics that deals with symmetry.