noun.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); often: such a machine built to resemble a human being or animal in appearance and behavior —often used before another noun

• Today, robots are operating on or around the Moon and Mars.
• 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.

noun.a device that automatically performs complicated, often repetitive tasks (as in an industrial assembly line) —often used before another noun

• As a sign of the times, paleontologists themselves have taken to … designing dinosaur robots and displays …
• the use of robots in car manufacturing

noun.a mechanism guided by automatic controls

• … factories run by robots producing many replicas of one product.
• a robot airplane