Definition from Wiktionary, the free dictionary
Etymology 1 
- a generic term meaning "drum"
- a traditional Korean double-headed barrel-shaped drum, played with one hand and one stick, and used in Korean folk music
Etymology 2 
First recorded in the Hunmong jahoe, 1527, as 북.
- a shuttle (used in weaving and sewing machines)
Etymology 3 
Of uncertain origin. Perhaps cognate with the above Etymology 1 and 2 in the sense of bulge.
Etymology 4