Nanosecond Share definition Flag A nanosecond is the time that takes the red light to turn green and the car that is behind you to honk three times cling!(Green light) HONK HONK HONK! nanosecond! Nanosecond by jackts9999 May 4, 2009 0 0 Get merch Get the Nanosecond mug. Buy Now — $32.95 See more merch