identity >> ʌɪˈdɛntɪti
Definition: [noun] the fact of being who or what a person or thing is.
Example: he knows the identity of the bombers
Definition: [noun] a close similarity or affinity.
Example: an identity between the company's own interests and those of the local community
Definition: [noun] a transformation that leaves an object unchanged.
Definition: [noun] 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.