The phrase "shoe sole" refers to the bottom part of a shoe that touches the ground. It is the part that provides traction and protection to our feet while walking or running. Full definition
With the microscope, he created an image of the surface of a synthetic rubber commonly used in shoe soles and pavement. (discovermagazine.com)
These materials are familiar, taken from quotidfan objects - his ongoing series The weight of thought for example, repurposes leather and rubber shoe soles. (jonathanferraragallery.com)
I tried making falafel once, (a long time ago when I was still stuffing my face with meat) and it totally tasted like shoe soles, so I let go of the idea. (iheartvegetables.com)