A Robot is machine which can automatically perform tasks without the intervention of a human. Traditionally, robots have been mechanical systems controlled by a programmable computer, but advances in software have resulted in programs that fit this definition. (These programs are colloquially known as bots.) In general, a robot is a machine that can act as a the agent of a human without being under the direct control of that human.
From Meriam-Webster a robot is "a machine that looks like a human being and performs various complex acts (as walking or talking) of a human being; also : a similar but fictional machine whose lack of capacity for human emotions is often emphasized b : an efficient insensitive person who functions automatically" 
In practice the definition of a robot is somewhat fluid. In general, to call something a robot, it must fulfill the following criteria:
- It must be artificially constructed.
- It must be able to sense some aspect of its environment.
- It must be able to alter its behavior based on inputs from the environment.
- It must be programmable.
Other behaviors that are often assiciated with robots, but are not strictly needed to meet the definition, are:
- It can manipulate objects in its environment.
- It may have specific tasks to perform.
- It may have an advanced decision making ability.
- It may resemble an living creature (Zoomorphic), in part or in entirity. Possible examples include: humans, dogs, insects, snakes, etc.
- It may be autonomous.
The idea of a machine that is cabable of doing what would normally be a human's work seems to be found in any culture able to produce mocerately complex mechanisms. Earliest examples are found in Greek mythology, and include mechanical servants created by the god Hephaestus and Talos, a mechanical man made of bronze.
The first use of the word Robot is attributed to Josef Čapek, a Czech writer. However, it was his brother Karel whose play R.U.R. (Rossum's Universal Robots) brought the term to the world's attention. The word robot was made from czech word robota, which means corvée in english.
The most popular applications of robotics is in manufacturing.
While Industrial robots were first marketed in 1960,
It has only been recently that consumer robotic products have appeared on the market. Among the most popular are the Sony's Aibo, Wowee's Robosapien, Roboraptor, and Robosapien V2, and the as-yet un-released Pleo.