Electronic refers to any device that is powered by electricity rather than by some other source of energy such as water (hydropower), gasoline (internal combustion engine), or steam, and uses vacuum tubes or transistors to perform tasks through the control of the movement of electrons in the device.
Early electronic devices
Early electronic devices used vacuum tubes rather than integrated circuits, which required a much larger device than is the case with much smaller integrated circuits. Early computers filled entire rooms, while radios, televisions and amplifiers were quite large. Devices using vacuum tubes gave off a great deal more heat than integrated circuits, requiring enough space in the device to dissipate heat.
When the transistor was invented, it replaced the vacuum tube, resulting in much smaller devices, much less heat, and more efficient use of energy. Integrated circuits are now used which link billions of transistors within a very small space. This allows the design of very powerful computers, and the use of integrated circuits to control functions in common household appliances such as coffee makers and telephones.
Electronic musical instruments
Electronic musical instruments are those which pick up and amplify sound waves, or, in the case of electric guitars, the movement of the strings themselves. Such instruments can also process sound electronically, producing a wide spectrum of different voices. Electronic music synthesizers produce sounds purely electronically by propagating various sound waves, and then processing and modulating them in various ways to mimic analogue instruments, or to produce new sounds that bear no resemblance to those produced by any other instrument.