Source : Webster's Revised Unabridged Dictionary (1913)

Launder \Laun"der\, n. [Contracted fr. OE. lavender, F.
   lavandi[`e]re, LL. lavandena, from L. lavare to wash. See
   {Lave}.]
   1. A washerwoman. [Obs.]

   2. (Mining) A trough used by miners to receive the powdered
      ore from the box where it is beaten, or for carrying water
      to the stamps, or other apparatus, for comminuting, or
      sorting, the ore.

Launder \Laun"der\, v. i. [imp. & p. p. {Laundered}; p. pr. &
   vb. n. {Laundering}.]
   1. To wash, as clothes; to wash, and to smooth with a
      flatiron or mangle; to wash and iron; as, to launder
      shirts.

   2. To lave; to wet. [Obs.] --Shak.

Source : WordNet®

launder
     v 1: cleanse with a cleaning agent, such as soap, and water;
          "Wash the towels, please!" [syn: {wash}]
     2: convert illegally obtained funds into legal ones