Shell and Hull

Shell

The word shell refers to a hard outer layer found on some animals and insects. It can also refer to the hard covering of an egg or nuts.
Ex: I am not very good at breaking eggs. I tend to leave pieces of the shell floating in the bowl along with the yolk.
Ex: My grandmother has a nutcracker that opens the shell of nuts so you can easily get to the edible meat.
The word shell can also refer to the outer structure or frame of a building. The building is not usually furnished or occupied.
Ex: The house we are building is still just a shell. At first glance, it does not look like a home, but we hope to have it finished soon.
Ex: It is difficult to decide if this is the office space we want as the building is just a shell. You have to use your imagination to picture it inhabited and in use.

Hull

The word hull can be used to refer to the outer layer of fruit or covering for seeds. In this case, it is a synonym for husk.
Ex: The hull of a strawberry is edible. At first sight it does not appear attractive or appetizing, but it is really a nutritious and tasty part of the fruit.
Ex: My pear's hull is spotted, but my mother always tells me that it is normal and will not affect the taste of the fruit. As a matter of course, I eat them no matter what they look like.
The word hull can also refer to the lowest part of a ship that is submerged. It is usually hollow and supports the frame of the ship.
Ex: The hull of the ship rose and fell with the waves. Nothing proved to be an obstacle as it cut across the ocean.
Ex: You should not use your hull for storage. If you feel the need to store things on the boat you should target the trunks in the main cabin.