dredgeverb definition in Coastlines and the sea topic from the Oxford Advanced Learner's Dictionary
verb: Coastlines and the sea topic
[transitive,intransitive]dredge (something) (for something)to remove mud, stones, etc. from the bottom of a river, canal, etc. using a boat or special machine, to make it deeper or to search for somethingThey're dredging the harbour so that larger ships can use it.They dredge the bay for gravel.