Robot

Robots are electronic/mechanical machines, able to perform tasks as per a set of specific preprogrammed parameters. Another common characteristic is that by its appearance or movements, a robot often conveys a sense that it has intent or agency of its own. The word robot can refer to both physical robots and virtual software agents, but the latter are usually referred to as bots. There is no consensus on which machines qualify as robots, but there is general agreement among experts and the public that robots tend to do some or all of the following: move around, operate a mechanical limb, sense and manipulate their environment, and exhibit intelligent behavior, especially behavior which mimics humans or other animals. As a means of preventing robots from becoming a threat to their environment, many of them are programmed to adhere to certain guidelines or "laws". As per science fiction writer Isaac Asimov, the Three Laws of Robotics are:


 * 1) A robot may not injure a human being or, through inaction, allow a human being to come to harm.
 * 2) A robot must obey any orders given to it by human beings, except where such orders would conflict with the First Law.
 * 3) A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.

Androids
Androids are robotic creations whose physical appearance is patterned after that of a humanoid. While all androids are robots, not all robots are androids. Some androids bear an appearance so similar to a normal human being, that they can often fool various means of perception be it ocular, electronic or otherwise.

Droids
A "droid" is merely another term used for robot, although the word itself is derivative of the word Android. Conversely however, droids are not necessarily androids as many have physical appearances that are not based on that of living beings. The term droid was popularized by the Star Wars film franchise, but has since become part of general sci-fi vernacular.