kapok

kapok - n., a massive tropical tree with deep ridges on its trunk; the silky fibers from the seed pods of same tree, used for insulation and filler (in pillows, mattresses, et cet.).


Only not so much so used, having been largely replaced by man-made fibers. The inevitable Wikipedia article has pictures. The name comes from the Malay word for the tree, kapoq, though the tree is in fact native to tropical Central America and west Africa as well as southeast Asia.

---L.