An electronic oscillator is an circuit that produces a repetitive electronic signal. That signal is often a sine wave or a square wave.
A low-frequency oscillator is an electronic oscillator that generates an AC waveform between 0.1 Hz and 10 Hz. A low frequency oscillator is generally used in the field of audio synthesizers to distinguish it from an audio frequency oscillator.
An oscillator is basically an amplifier that provides itself with an input signal. It is a non-rotating device for producing (AC) alternating current; of which the output frequency is determined by the characteristics of the device. The fundamental purpose of an oscillator is to create a specific waveform at a constant peak amplitude and exact frequency and to maintain this waveform within certain limits of amplitude and frequency.