An apron is a piece of leather material that covers the top of the vamp around the perimeter, almost like an apron that you might wear. It sits just in front of a shoe’s lacing system, and then is connected to the vamp leather with a stitch. Typically, this does not extend to the end of the toe. The apron toe features a seam that starts at the middle of the toe, runs around the shoe, and ends at the middle of the heel.
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.