Dictionary.com
Thesaurus.com

slipsole

American  
[slip-sohl] / ˈslɪpˌsoʊl /

noun

  1. an insole placed in a shoe for warmth or to adjust the size.

  2. a thin strip of material, as leather, set between the insole and the outsole of a shoe, usually for height.


Etymology

Origin of slipsole

First recorded in 1905–10; slip 1 + sole 2