A cyborg, or "cybernetic organism", was initially defined as follows: "The Cyborg deliberately incorporates exogenous components extending the self-regulating control function of the organism in order to adapt it to new environments." This verbose sentence can be simplified to, the cyborg represents "a notion of human-machine merging".
This concept, dear to science fiction writers, is all about humans becoming stronger, faster, and more powerful through the use of integrated technology. One example of this is the cochlear implants used to help deaf people hear again; these implants are more than hearing aids, since they interface directly with nerve endings. Another example is prosthetics, which allow people who have lost limbs in accidents to function almost as before.
Andy Clark, a cognitive scientist, sets out to recount why, in his eyes, "we shall be cyborgs not in the merely superficial sense of combining flesh and wires but in the more profound sense of being human-technology symbionts: thinking and reasoning systems whose minds and selves are spread across biological brain and nonbiological circuitry." This is quite a statement, if you look at it closely: he is suggesting that the systems we will incorporate into our bodies will be thinking systems, that they will merge with our minds, and that they will be come self-aware.
Via Marie-Anne Paveau