The microwave oven got its name from the type of electromagnetic radiation it uses to cook food. Microwaves are a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter, falling between radio waves and infrared radiation on the electromagnetic spectrum.
The idea of using microwaves for cooking was discovered accidentally by Percy Spencer, an engineer at Raytheon Corporation, in 1945. While working on magnetrons (vacuum tubes that generate microwaves for radar systems) during World War II, Spencer noticed that a candy bar in his pocket had melted when he was near the magnetron. Intrigued by this observation, he conducted further experiments with other food items, and they too were quickly cooked using microwaves.
The first microwave oven, called the "Radarange," was introduced in 1947 by Raytheon. It was quite large and expensive, and its primary use was in commercial settings like restaurants and ships.
Regarding the name choice, "microwave" was preferred over "radar oven" or similar names to emphasize the use of microwaves as the cooking mechanism. While microwaves and radar both utilize electromagnetic waves, they operate in different frequency ranges. The term "microwave" directly links the cooking method to the type of radiation used, making it more descriptive of the technology.
Using the term "radar oven" might have caused confusion as it could imply a connection to radar systems in terms of functionality, leading people to assume that the oven is somehow related to detecting objects like radar devices do. By using "microwave," it makes it clear that it is the microwave radiation that is being used for cooking purposes. The term has become so ingrained in common usage that it has remained the standard name for these appliances ever since.