1911 Encyclopædia Britannica/Oakum

OAKUM (O. Eng. ácumbe or—œcumbe, tow, literally “off-combings”), a preparation of tarred fibre used in shipbuilding, for caulking or packing joints of timbers in wood vessels and the deck planking of iron and steel ships. Oakum is made by preference from old tarry ropes and cordage of vessels, and its picking and preparation has been a common penal occupation in prisons and workhouses. White oakum is made from untarred materials.