dredger
Concise Oxford English Dictionary © 2008 Oxford University Press:
dredge1
▶verb
- 1 clean out the bed of (a harbour, river, etc.) with a dredge.
■ bring up or remove with a dredge.
- 2 (dredge something up) bring something unwelcome and forgotten to people's attention.
– derivatives
dredger noun.
dredger noun.
– origin C15 (orig. in dredge-boat): perh. rel. to MDu. dregghe ‘grappling hook’.
Concise Oxford English Dictionary © 2008 Oxford University Press:
dredge2
▶verb sprinkle (food) with sugar or another powdered substance.
– origin C16: from obs. dredge ‘sweetmeat, mixture of spices’, from OFr. dragie, perh. via L. from Gk tragēmata ‘spices’.
'dredger' also found in these Oxford entries:

