Oak″um (ōk″ŭm), n. [AS. ācumba; pref. ā- (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.