organized crime

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Crime committed by groups engaged in planned and sustained criminal activities.
• noun The people and the groups involved in such criminal activities.

from the GNU version of the Collaborative International Dictionary of English.

• noun Groups of persons organized for illegal purposes, such as bootlegging, conducting illegal gambling, loansharking, extortion, etc.; -- a general term encompassing most forms of criminal groups, but especially those that are consolidated into “families” more or less recognizing each other's different regions of operation; sometimes considered synonymous with the mafia or the syndicate.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A set of large criminal organizations (often competing for markets and territories) that deal in illegal goods and services.
• noun The crimes perpetrated by those organizations.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun underworld organizations