For example, it could be:
* A flash of lightning: This is a common image associated with storms.
* A camera flash: This is used to illuminate a scene for photography.
* A sudden burst of sunlight: This could happen when you step out of a dark place into the sun.
* A laser beam: This could be used for cutting, pointing, or even as a weapon.
* A metaphorical representation of a sudden realization or inspiration: This is often used in literature and poetry.
To help me understand what you mean, please provide me with more information:
* What is the context? What is happening around this "single stab of bright light"?
* What is the effect of the light? Does it scare someone? Does it make something visible? Does it change the atmosphere?
The more detail you give me, the better I can understand what you're looking for.
