A robot is a human-made machine which is built for the purpose of carrying out tasks on behalf of humans. Robots may come in different shapes — one may look like a simple machine, an animal, or may appear in human form. A robot which has a human-like appearance is called a humanoid robot. When a humanoid robot is covered with a human-like skin and looks exactly like a human being, it is called an android (robot in male form) or gynoid (robot in female form).
DER 01 is the first gynoid ever built. It was built in Japan (see image). Japan and South Korea are the only countries which have been able to build a number of androids and gynoids. EveR-2 (see image) is the world's first android made in South Korea. EveR-1 (see image) is the world's second gynoid made in South Korea that can also express human emotions and can speak Korean and English. The skins of androids and gynoids are made of silicone, which is highly realistic.
Most robots, however, look nothing like people at all, and are usually built to perform specialized manufacturing operations. Robots are also available in kit form for educational and hobbyist use, as well as pre-built, and vary widely in complexity from simple sense circuits on wheels to autonomous appliances like the iRobot Roomba vacuum cleaner. Robots are also used for specialized tasks in war and law enforcement situations (especially disarming bombs) and space exploration.
The Robot Apocalypse is a significant feature of some postapocalyptic science fiction, most notably Dune and The Matrix. An actual robot apocalypse, however, based on what we can safely predict from current technology, is somewhat unlikely.