The Collaborative International Dictionary of English v.0.48:

Swash \Swash\, n. [Cf. Swash, v. i., Squash, v. t.] (Arch.)
   An oval figure, whose moldings are oblique to the axis of the
   work. --Moxon.
   [1913 Webster]

   Swash plate (Mach.), a revolving circular plate, set
      obliquely on its shaft, and acting as a cam to give a
      reciprocating motion to a rod in a direction parallel to
      the shaft.
      [1913 Webster]