Source : Webster's Revised Unabridged Dictionary (1913)

Dredge \Dredge\, v. t. [imp. & p. p. {Dredged}; p. pr. & vb. n.
   {Dredging}.]
   To catch or gather with a dredge; to deepen with a dredging
   machine. --R. Carew.

   {Dredging machine}, a machine (commonly on a boat) used to
      scoop up mud, gravel, or obstructions from the bottom of
      rivers, docks, etc., so as to deepen them.

Dredge \Dredge\, n. [OE. dragge, F. drag['e]e, dredge, also,
   sugar plum; cf. Prov. dragea, It. treggea; corrupted fr. LL.
   tragemata, pl., sweetmeats, Gr. ?, fr. ? to gnaw.]
   A mixture of oats and barley. [Obs.] --Kersey.

Dredge \Dredge\, n. [F. dr[`e]ge, dreige, fish net, from a word
   akin to E. draw; cf. D. dreg, dregge, small anchor, dregnet
   dragnet. ????. See {Draw}.]
   1. Any instrument used to gather or take by dragging; as:
      (a) A dragnet for taking up oysters, etc., from their
          beds.
      (b) A dredging machine.
      (c) An iron frame, with a fine net attached, used in
          collecting animals living at the bottom of the sea.

   2. (Mining) Very fine mineral matter held in suspension in
      water. --Raymond.

Dredge \Dredge\, v. t.
   To sift or sprinkle flour, etc., on, as on roasting meat.
   --Beau. & Fl.

   {Dredging box}.
   (a) Same as 2d {Dredger}.
   (b) (Gun.) A copper box with a perforated lid; -- used for
       sprinkling meal powder over shell fuses. --Farrow.

Source : WordNet®

dredge
     n : a power shovel to remove material from a channel or riverbed

dredge
     v 1: cover before cooking; "dredge the chicken in flour before
          frying it"
     2: search (as the bottom of a body of water) for something
        valuable or lost [syn: {drag}]
     3: remove with a power shovel, usually from a bottom of a body
        of water