identity: [16] The historical meaning of identity is best preserved in its derivative identical [17] – ‘the same’. For its ultimate source was Latin idem ‘same’, a pronoun (formed from id ‘it, that one’ with the suffix -dem) used in English since the 17th century for referring to a previously cited author or text. This formed the basis of late Latin identitās, which meant literally ‘sameness’; the main meaning of its English descendant identity, ‘individuality, set of definitive characteristics’, arose from the notion of something always being the same or always being itself (rather than something else).
