Noun
an operator that leaves unchanged the element on which it operates
Source: WordNetA ring of polynomials in any number of variables over a ring of coeffcients that has an identity element and a finite basis, itself has a finite basis. Emmy Noether
the identity under numerical multiplication is 1 Source: Internet
This identity is of prime importance in simplifying algebraic expressions: :: ; Identity element : The multiplicative identity is 1; anything multiplied by one is itself. Source: Internet