From Longman Dictionary of Contemporary Englishoakumoa‧kum /ˈəʊkəm $ ˈoʊ-/ noun [uncountable] TTWsmall pieces of old rope used for filling up small holes in the sides of wooden ships
Examples from the Corpus
oakum• The cracks between the logs are chinked by oakum that I have laboriously pounded in.• Luckily I had a big case of oakum downstairs.• I sat on the floor among them and picked oakum.• Below: Caulking - filling the gaps between planks with rolled oakum.• Instead, he amused himself by pulling out the oakum from between the logs of the cabin.Origin oakum Old English acumba “material separated with a comb” 