What is second curtain flash?

The Basics:

Second curtain flash is where the photographer needs to use a long shutter speed to expose for the background, together with a flash to illuminate a foreground subject. With Second Curtain Flash – also known as Rear Curtain Sync – the flash fires at the end of the exposure. This can create interesting effects in night time photography, such as trailing head lights, to suggest a notion of fast movement.
OTHER WORDS UNDER S