Question
What is major disparity between fasteners, bolts and screws?
Answer
Fastener is a broad term to explain something that is used as a restraint for holding things together to other things.
Key physical distinction between screws and bolts is that screws are totally full of threads even as bolts contain shanks without threads. Yet, a better interpretation of differences between two is to bolts are always fitted with nuts. On contrary, screws are in general used with tapped holes.