I've read more than once on a few DBZ websites and character shrines that 18 used to be human, got turned into a cyborg, and then got so many mechanical implants in her by Dr. Gero, she turned into an android.
Ugggh. Reading that makes me shudder.
Why? What is so wrong about that statement? Androids are totally mechanical and so, if a person got enough mechanical parts, they could be transformed into an android, right?
NO!
For some reason, people seem to think that there is only a slight difference between androids and cyborgs. Some people even think that the two words are totally interchangeable. But they're wrong. These words are not synonyms. An android is merely a robot with human form. A robot is completely and utterly man-made, something not created in nature. It does not have a soul, nor a living, beating heart, and a robot that looks like a human - an android - is no different.
There is nothing robotic about a cyborg, who is a bionic human. In fact, the word "cyborg" is a shortened term for "cybernetic organism."
"The first syllable of 'cyborg' derives from 'cybernetics' (from the Greek for 'steersman'), which is the study of control systems and comparisons between artificial and biological systems. The second syllable comes from 'organism', which adds emphasis to the significant part that will still be played by the human being who acts as a host to the technology. The cyborg's abilities extend beyond human limitations by mechanical, electronic or chemical means incorporated within the body."Going back to the word bionic, it has many, slightly varied definitions in numerous dictionaries. Though each definition may be slightly different, they all keep the specific emphasis of the enhancement or the replacement of parts in the natural human being through artificial means. The key point of the cyborg is that he is a human being whose body is host to technology that enhances him or replaces parts. This idea is not present in the android, whose key concept is that of being a robot with human form, a completely artificial being, entirely man-made.
- from Cyborg: the Man-Machine by Marie O'Mahony
When you really begin to understand what a cyborg is, it hits you that the old man on the bench with a pair of glasses is technically a cyborg. The glasses are enhancing his natural vision, replacing the vision that has deteriorated. A woman with a pacemaker in her chest is a cyborg also, with this device that regulates and forces her heart to beat at a steady rhythm. And a young boy with a prosthetic leg is also a cyborg, the artificial limb replacing what was lost.
Meanwhile, most people conjure up images of muscular soldiers with mechanical arms when they hear the word "cyborg." There's nothing wrong with it, but it creates the false idea that a cyborg is enhanced only through mechanical means, or that the cyborg is something like a creature with a metal skeleton and living skin. It is therefore easy for people make ignorant assumptions such as the one that an android and cyborg are nearly one in the same or that a cyborg could turn into an android, seeing as they are both mechanical and humanoid. But like I stated earlier, an android is only a robot, and a cyborg is always, always a human being.
Even when a human being relinquishes its entire body to technology, when it replaces all of its limbs and internal organs, even parts of its brain, it will still be a cyborg. What humanity is left in a full-conversion cyborg is questionable, and this topic is in fact explored in Ghost In the Shell whose main character, Motoko Kusanagi, is a full-conversion 'borg, but the fact that it was a natural human to begin with is all the evidence you need to claim it is not an android.
A cyborg can never be turned into an android, because a human being can never become a complete robot. A cyborg is a man-machine, a mixture of natural and artificial, and an android is completely artificial, no matter if it has living skin on its artificial body or living eyes hardwired to a positronic matrix. It will never be a true human...merely a humanoid.
End Note: I would like to make it clear that when I refer to the "true human" I am simply referring to a human that is born from other humans. That whole other argument on what constitues being human in the sense of being "alive," is something I won't touch upon that here. Just watch Star Trek or Chobits or something if you want to delve into that stuff...