Goodyear welt
A shoe construction method where the upper, lining, and welt strip are stitched together, then a second seam attaches the welt to the sole. Resoleable and extremely durable.
Goodyear welting is one of two construction methods (the other being Blake stitching) that allow shoes to be resoled. The upper, lining, and a strip of leather called the "welt" are stitched together with what's called the inseam; a second outer seam through the welt attaches the sole. When the sole wears out, a cobbler can cut the outer stitch, replace the sole, and re-stitch — the upper itself never gets damaged.
The construction is more expensive (slower to assemble, more leather required) but produces shoes that can last 15–30 years with periodic resoling. Allen Edmonds, Alden, and most quality British shoemakers (Crockett & Jones, Cheaney, Tricker's) use Goodyear welt as the default for dress and country shoes.
The alternatives: Blake-stitched (a single seam through the insole, upper, and sole — common in Italian dress shoes, can be resoled but with limits) and cement (glued sole, can't be resoled, lifespan typically 1–4 years). Most "welted" shoes under $200 are actually cement-construction with a fake welt for appearance; real welted construction at retail starts around $300 for the entry tier (Allen Edmonds outlets, Meermin) and $500+ for mainstream brands.
Full canvas (tailoring)
A jacket construction where the canvas interlining is stitched (not glued) to the wool throughout the front. Drapes naturally, breaks in to your body, lasts decades.
Single-needle stitching
A shirting construction where seams are sewn with one needle making one row of stitches at a time. Slower, more precise, more durable than double-needle.