Meaning

noun loose hemp or jute fiber obtained by unravelling old ropes; when impregnated with tar it was used to caulk seams and pack joints in wooden ships

originFrom Late Middle English okom, okome (“oakum”) [and other forms], from Old English ācumba (“oakum”, literally “that which has been combed out, off-combings”) [and other forms], from ācemban (“to comb out”), from Proto-Germanic *uz- (from Proto-Indo-European *ud-s-, *ūd- (“out; up”), or *h₂ew- (“away from, off”)) + *kambijaną (“to comb”) (ultimately from *ǵómbʰos (“row of teeth; tooth; peg”),…

Etymology from Wiktionary, CC BY-SA 3.0