A flash is a bright light that you only see for a very, very short time. When you take a photo with a camera in dim light you usually use a flash to light the objects in the photo up so you will be able to see them.
A flash can also be used to describe something you only see for a very short time, or didn't quite see clearly, as in "I saw the rabbit flash by".
Fis forFlashlight
A flashlight, sometimes called a torch, is a small device that has a handle at one end and a light at the other end. You use it for finding your way around somewhere dark that doesn't have any other light sources, like at night when you are camping, or if there is a power failure, or in a cave.
A flaw is a quality of something that stops it from being perfect.
A flaw is also called a defect or imperfection.