\Oak"um\, n. [AS. [=a]cumba; pref. ? (cf.G. er-, Goth.
us-, orig. meaning, out) + cemban to comb, camb comb. See
{Comb}.]
1. The material obtained by untwisting and picking into loose
   fiber old hemp ropes; -- used for calking the seams of
   ships, stopping leaks, etc.
2. The coarse portion separated from flax or hemp in
   nackling. --Knight.
{White oakum}, that made from untarred rope.