A form of plastic invented in the 1930s by the Molex company. The material was developed by the late Frederick August Krehbiel. In 1938, he founded the Molex Products Company in Brookfield, Ill. to manufacture a variety of products from this material, including clock cases, flower pots, valve wheels and salt tablet dispensers.
In the 1950s, Molex rapidly penetrated the appliance market with its low-cost connector terminal blocks. The company launched its first plug and receptacle connector line in 1953. In 1960, the company introduced its first nylon plug and receptacle line, marking its evolution from a manufacturer of a material called Molex to an electronics corporation named Molex. [Source: Molex Web site]
Today when the word Molex is used by the computer enthusiast it is used to refer to the standard power connectors found in modern computers. It is the nylon plug and receptacle; a plastic end to which four wires are attached and are used for connecting many devices such as hard disks, CD-ROMs, graphics cards, storage devices, and more.