They are called threads
The Bottle Deposit (part 2)
The cortex
The frontal bone contains what is commonly known as eyebrow ridges. This bone is part of the skull.
Lugs
The screw part at the end of the headpiece is for tuning.
The main parts of a screw include: Head: The top part of the screw that is usually slotted or Phillips-shaped for turning with a screwdriver or drill. Shank: The cylindrical body of the screw that has threads wrapped around it. Threads: The spiraled ridges on the shank that grip and secure materials when the screw is turned. Point: The sharp or tapered end of the screw that facilitates easy penetration into materials. Root: The bottom of the threads, where they meet the shank. Length: The measurement from the tip of the screw to the bottom of the head. These components work together to fasten materials by turning the screw into them
A CNC screw machine produces small parts. Despite its name, the part need not necessarily be a screw. They can also produce things like nuts and bolts.
friction ridges
It is part ridges.
The 'screw' part, as in 'screw-driver'
Papillary Layer
The screw part or the part that holds it in place in many cases is a screw, so in that case it could be held up as an example of a screw. I doubt however if a light bulb with a bayonet fitting could be held as an example of a screw.