The inner sole of a shoe, beneath the foot.
Insole can describe a structural layer inside a shoe or the softer layer immediately beneath the foot. Carmina describes the leather insole as part of the shoe body. In Blake construction it is stitched directly to the sole with the upper, while Goodyear construction introduces a welt between these assemblies. Grenson describes the ribbed insole as the foundation of a Goodyear-welted shoe and separately names an inner sock covering it. ASICS uses insole for a running shoe’s soft foam sockliner. Checking the construction context helps establish which layer a description means.
In job listings
The insole is more likely to come up in a fitting or a product brief than in a listing. A footwear advisor may discuss how it feels and whether it can be replaced, while a developer specifies its material and shape. Search local jobs for “footwear”.