the fact of being who or what a person or thing is.
he knows the identity of the bombers
a close similarity or affinity.
the initiative created an identity between the city and the suburbs
a transformation that leaves an object unchanged.
Any object, indeed any molecule, will contain at least one of these symmetry elements - the operation C 1 known as the identity operation - a rotation of 360°, the equivalent of doing nothing.
the equality of two expressions for all values of the quantities expressed by letters, or an equation expressing this, e.g., ( x + 1) 2 = x 2 + 2 x + 1.
Identity and equality are two fundamental binary relations which relate expressions of a given type.