noun
: an identity element (as 1 in the group of rational numbers without 0 under the operation of multiplication) that in a given mathematical system leaves unchanged any element by which it is multiplied
noun
: an identity element (as 1 in the group of rational numbers without 0 under the operation of multiplication) that in a given mathematical system leaves unchanged any element by which it is multiplied
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012