The inside sole of a boot or shoe; also, a loose, thin strip of leather, felt, etc., placed inside the shoe for warmth or ease.
The inner lining of a shoe that cushions the foot from the sole. The thickness of the lining is often directly related to the comfort of the shoe.
the layer of leather between the foot and the outsole, or bottom, of the boot. The insole forms the inner foundation of the boot to which the outsole is attached.