https://en.oxforddictionaries.com/definition/robot

A machine capable of carrying out a complex series of actions automatically, especially one programmable by a computer.

https://www.merriam-webster.com/dictionary/robot

1 : a machine that resembles a living creature in being capable of moving independently (as by walking or rolling on wheels) and performing complex actions (such as grasping and moving objects) 
//When the next space launch heads for Mars, on board will be dozens of tiny mobile robots that will fan out across the Martian landscape, exploring every nook and cranny.

— Michael Bowker 

often : such a machine built to resemble a human being or animal in appearance and behavior  
//While science fiction robots have been capable of independent thought, emotions, even a little cooking and sewing, scientists are finding that endowing a mechanical being with even the most basic human functions is a monumental challenge. 

— Greg Freiherr  
 
//As a sign of the times, paleontologists themselves have taken to … designing dinosaur robots and displays … 

— Malcolm W. Browne  

—often used before another noun  
//a robot dog 

//a robot servant 

— compare android

2a : a device that automatically performs complicated, often repetitive tasks (as in an industrial assembly line) 
//the use of robots in car manufacturing

//... factories run by robots producing many replicas of one product.

— Morris Philipson 
—often used before another noun 
//For fluid applications, especially in the automotive industry, the robot arm must have extremely flexible movement.

— Harry H. Poole
   
b : a mechanism guided by automatic controls 
//a robot airplane
  

3 : a person who resembles a machine in seeming to function automatically or in lacking normal feelings or emotions 
//... seems to believe that professors are robots, students are superficial, grade-hungry receptacles …

— Micaela Rubalcava 

See also https://www.wired.com/story/what-is-a-robot/