Goodyear welt construction is a shoemaking method where a strip of leather (the welt) is stitched to both the upper and the insole, then the outsole is stitched to the welt. This creates a more durable, water-resistant, and repairable shoe than cemented construction — the sole can be resoled multiple times without damaging the upper. It's the standard used by the world's most respected leather footwear brands.