The Collaborative International Dictionary of English v.0.48:

Priming \Prim"ing\, n.
   1. The powder or other combustible used to communicate fire
      to a charge of gunpowder, as in a firearm.
      [1913 Webster]

   2. (Paint.) The first coating of color, size, or the like,
      laid on canvas, or on a building, or other surface.
      [1913 Webster]

   3. (Steam Eng.) The carrying over of water, with the steam,
      from the boiler, as into the cylinder.
      [1913 Webster]

   Priming of the tide. See Lag of the tide, under 2d Lag.


   Priming tube, a small pipe, filled with a combustible
      composition for firing cannon.

   Priming valve (Steam Eng.), a spring safety valve applied
      to the cylinder of a steam engine for discharging water
      carried into the cylinder by priming.

   Priming wire, a pointed wire used to penetrate the vent of
      a piece, for piercing the cartridge before priming.
      [1913 Webster]