The word robot was first used in 1920 by Czech playwright Karel Chapek. In Slavic languages the word means "hard work". Chapek used it to describe intelligent machines that were able to operate on their own and in doing so relieve humans of hard and harmful work.
To this day it remains the core definition of a robot – a machine, most likely moving or with moving parts, designed to replace a human in dangerous or monotonous operations that is capable of executing a set of actions without constant input from a human.
We also refer to automatic space probes as robots because they are designed to operate in the most extreme environments and can perform many tasks without human input because of constrains of the immense distances in space. Because of great importance of robots to its operation NASA plays an important role in furthering development of robotics via its Robotics Alliance Project.
Today there are many important industries that simply cannot function without robots (semiconductor manufacturing, electronics assembly) and many more that would be severely hampered without robots, such as automobile manufacturing.