While possibly an aphetic form of espine (cf. DMF and FEW), the word in Anglo-Norman is more likely to be a borrowing from English (Old English pin), which itself is believed to derive from Classical Latin pinna ('feather', see penne1).
(
1396-1404
) une petit toneux d'argent verrez, coveré, pur mettre lescive pur laver les pins
213.R752
2footwearleather patch or laminate that is attached to the vamp of the shoe for custom fitting:
(
MS: s.xiii
) Pictaciarii viles sunt qui consuunt sotulares veteres renovando pictacia et intercutia, soleas et inpedias gloss: (L) vampes, les pinnes(var.
(D: s.xiii/xiv) empenes;
(D*: s.xiii/xiv) enpeyns, wanpeys
)i 197.24 and ii 129.24
pin2 (s.xiii1)