The Claws. the big one if for eating and drinking and the little one also helps with eating and drinking.
it is called the claws
its called a pincer
Pincer, to technically, Cheliped.
When a hermit crab grows it's called molting, they go underground for months to molt.
It uses its shell and its large pincer.
It grows back
Its shell and its pincers (particularly the larger pincer) help protect it.
Here in Australia. when we refer to the large front legs used for fighting and defence, and containing far more meat than the other eight legs, crabs' claws.
In parts of the Caribbean we call it the Gundi. Not sure of the spelling. Could be Gundee. Can't find it in a dictionary, anyway. If someone has the correct spelling, do share. It is also referred to as the armor claw, with the smaller called the feeder claw. On forums you will see it referred to as the BP (big pincher) and LP (little pincher).
Currently, pincer does not have an evolution.
If you are reffering to the trap in crab fishing it is called the "pot".
A crab's shell is called a carapace.