A robot is any automatically operated machine that replaces human effort, though it may not resemble human beings in appearance or perform functions in a humanlike manner. By extension, robotics is the engineering discipline dealing with the design, construction, and operation of robots.
If you've got a robot in your home, most likely it's a robot vacuum cleaner or lawn mower. Although these machines give the impression that they're autonomous and semi-intelligent, they're much simpler (and less robotic) than they appear.
As a result, the word robot came to have several meanings, including "a human being who has become brutal and insensitive or machinelike because of overwork and mistreatment."