Electronic instruments are musical instruments that make sound primarily by way of electrically driven oscillators, such as the theremin or synthesizer.   A user interface device is used to control and/or adjust the properties of sound, such as frequency/pitch, intensity/dynamics, tone color/timbre, and/or duration/rhythm of each sound.

Electric instruments are referred to those musical instruments that use electronic circuits to reinforce means of amplification, such as the electric piano, electric guitar, etc.  A user interface is used for adjusting the sound.