What is the full form of slr?

SLR usually stands for Single-Lens Reflex. This is a type of camera. It uses a mirror and prism system. So, the photographer can see exactly what the lens will capture.

But sometimes, SLR can mean other things. For example, in banking, it can mean Statutory Liquidity Ratio. This is mostly used in India, I think. So it really depends on the context you are asking about, eh? I hope this is some help to you.