Vibrato is a technique of rapidly moving a note up and down in the direction of the adjacent strings. Vibrato is an important method of sustaining a note once it has been picked. It can also add expression to your playing.
Vibrato is usually found on long notes, or a note at the end of a phrase. Vibrato is usually played by moving the wrist away from the neck and back towards the neck, much like turning a doorknob several times in quick succession. The symbol for vibrato is a wavy line.
The following lick demonstrates the use of vibrato.