Lobbyists: Definition from Answers.com
Law Dictionary:
Lobbyists
Persons engaged in the business of persuading legislators to pass laws that are favorable, and to defeat those that are unfavorable, to their interests or the interests of their clients. The activities of lobbyists are regulated by statute in most jurisdictions; at the federal level such activities are subject to the provisions of the Lobbying Regulation Acts, 2 U.S.C. §§261-270.