Real
The Real is a term used by the psychoanalyst Jacques Lacan in his theory of psychic structures. For Lacan, the Real is the irreducible surplus of the 'outside world' that resists being turned into language (as the Symbolic) or into spatial representation (as the Imaginary). This the First-Order Real.
In the later Lacan, a Second-Order Real is formulated which is not "outside of" or "underlying" the Symbolic Order but is in fact a structural feature of it -- its lack.