oakum
/ˈəʊkəm/noun
mass noun
- chiefly historical loose fibre obtained by untwisting old rope, used especially in caulking wooden ships〈主史〉（尤用于填塞木船缝以防漏的）填絮, 麻絮。
词源
Old English ācumbe, literally 'off-combings'. The current sense dates from Middle English.