Damp n.
  1. Moisture; humidity; fog; fogginess; vapor.
  Night . . . with black air
  Accompanied, with damps and dreadful gloom.   --Milton.
  2. Dejection; depression; cloud of the mind.
  Even now, while thus I stand blest in thy presence,
  A secret damp of grief comes o'er my soul.   --Addison.
     It must have thrown a damp over your autumn excursion.   --J. D. Forbes.
  3. Mining A gaseous product, formed in coal mines, old wells, pints, etc.
  Choke damp, a damp consisting principally of carbonic acid gas; -- so called from its extinguishing flame and animal life. See Carbonic acid, under Carbonic.
  Damp sheet, a curtain in a mine gallery to direct air currents and prevent accumulation of gas.
  Fire damp, a damp consisting chiefly of light carbureted hydrogen; -- so called from its tendence to explode when mixed with atmospheric air and brought into contact with flame.