If you trawl through a large number of similar things, you search through them looking for something that you want or something that is suitable for a particular purpose. A team of officers is trawling through the records of thousands of petty thieves Her private secretary has carefully trawled the West End for a suitable show
a conical fishnet dragged through the water at great depths a long fishing line with many shorter lines and hooks attached to it (usually suspended between buoys) fish with trawlers
A large bag net attached to a beam with iron frames at its ends, and dragged at the bottom of the sea, used in fishing, and in gathering forms of marine life from the sea bottom
When fishermen trawl for fish, they pull a wide net behind their ship in order to catch fish. They had seen him trawling and therefore knew that there were fish We came upon a fishing boat trawling for Dover sole