properties /identity

How a shoe fastens to the foot — its closure mechanism, bucketed into the categories footwear retailers actually sell and filter by: lace-up (laces), slip-on (no fastening, the foot steps in / pull-on), hook-and-loop (an adjustable velcro strap), buckle (a buckle or monk-strap fastening), zipper (a zip entry), elastic / gore (a stretch gore or elastic panel, e.g. a Chelsea boot — a manufactured stretch closure, distinct from a plain slip-on), bungee (an elastic cord), and toggle (a cord-lock barrel). The buckle value subsumes the monk-strap dress shoe (a buckle fastening). It is the canonical footwear 'Closure' filter on Zappos, Nordstrom, REI and Clarks, statable of ALL footwear (Footwear, Boot, Sandal) — a sneaker laces, a loafer slips on, a kids' shoe is hook-and-loop, a sandal buckles, a boot zips. Distinct from `closure_type` (b84), which is the GARMENT fastening of upper-body apparel (pullover/button-front/half-placket/zip/snap) on a different branch with a disjoint vocabulary — a shoe is never button-front, a shirt is never lace-up — so they are separate properties, not synonyms. Distinct too from `strap_type` (the sandal strap CONFIGURATION — where the straps sit: slide, slingback, ankle-strap, thong …), which is orthogonal: a buckled sandal is strap_type=ankle-strap AND closure=buckle at once. It is an IDENTITY discriminator, not a buyable facet: on real catalogues closure is a CATEGORY filter that navigates to DIFFERENT listings (a lace-up and a slip-on of the same silhouette are distinct products, each its own SKU/reviews), never a single-product buy-box toggle — a given shoe simply IS a fixed closure. Grouped in the `identity` concern, so by the derived-axis rule it is NOT axis-eligible — a seller never offers one shoe across closures as buy-box versions. Optional and one-or-more: a listing states the closure(s) the shoe actually has — usually one, but genuinely multiple for dual-closure footwear (a tactical/combat boot with a lace-up front AND a functional side zip; a kids' sneaker with hook-and-loop AND a bungee), which a single-valued slot could not state; reused across all footwear.