The mid-sole - also known as the ’through’ - is a mostly piece of leather that is placed over the layer of cork which is in the cavity between the welt and insole, for protection. On the Vibram soles, we use an EVA mid-sole.
The shank is an internal part of the shoe which goes between the insole and outsole and provides stability to the shoe.
Sock lining is the inner part of the footwear that covers the insole (footbed) of our footwear. You touch this part with your foot when wearing shoes.