Thrum n.  [Written also thrumb.]
  1. One of the ends of weaver's threads; hence, any soft, short threads or tufts resembling these.
  2. Any coarse yarn; an unraveled strand of rope.
  3. Bot. A threadlike part of a flower; a stamen.
  4. Mining A shove out of place; a small displacement or fault along a seam.
  5. Naut. A mat made of canvas and tufts of yarn.
  Thrum cap, a knitted cap. --Halliwell.
  Thrum hat, a hat made of coarse woolen cloth. --Minsheu.