The Collaborative International Dictionary of English v.0.48:
Dragnet \Drag"net`\, n. [Cf. AS. dr[ae]gnet.] A net to be drawn along the bottom of a body of water, as in fishing. [1913 Webster]WordNet (r) 3.0 (2006):
dragnet n 1: a system of coordinated measures for apprehending (criminals or other individuals); "caught in the police dragnet" 2: a conical fishnet dragged through the water at great depths [syn: trawl, dragnet, trawl net]