cyEborg (s?'borg') n. A human who has certain physiological processes aided or controlled by mechanical or electronic devices. (Definition from American Heritage Dictionary)

What object/human combinations, then fall under the definition of a cyborg? A pacemaker, for one, fits the definition perfectly. It is a machine, inherently combined with the body to aide it. All manner of synthetic limbs function in the same way. From there it is not so hard to say that relying on a pair of glasses makes someone a cyborg, or even relying on clothing. William Mitchell takes this a step further writing in his book Me++: The Cyborg Self and the Networked City writing that gsince Neanderthal early-adopters first picked up sticks and stones, we have never been human." Thus, at least according to Mitchell, using any tool, any extension beyond the flesh, makes on a cyborg.