An object's casing is its outer cover or protective layer.
When we talk about a casing, we usually think about something like a phone or a computer that has a hard plastic or metal covering around it. This covering protects the device from getting damaged and also helps to make it look neat and tidy. It's kind of like wrapping a fragile vase in bubble wrap – you're putting a layer of protection between the thing inside (the vase) and the outside world.
To propose hypothetical cases.
To place (an item or items of manufacture) into a box, as in preparation for shipment.
That which encloses or encases.
Example: Some people like to split the casing of a sausage before cooking so it doesn't burst.
