Chorus: The chorus effect is a type of modulation that is created by splitting the original signal, changing the pitch slightly on one of the signals, delaying the signal a bit, and then playing the two together. The Low Frequency Oscillator LFO changes the signal slightly and then send the signal back delayed by milliseconds.
Simple Explanation: Harmonic sounds of a choir.
Effect Pedal Examples:
Common Internal Components:
Fifty Favorite Effect Pedals for Sale: