Is a chopper a helicopter?

We have all heard about Helicopters, seen in Movies, maybe many of us have had Helicopter/ Chopper rides. We have also Heard about Choppers like the police Choppers Or Rescue Choppers and so on. 

I always wondered Is Chopper and Helicopter are the same? Or is there any difference between at all?.

So did a bit of research to figure that out… Here is what I discovered.