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. {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.