noun, plural -bies, verb, -bied, -by⋅ing.| 1. | an entrance hall, corridor, or vestibule, as in a public building, often serving as an anteroom; foyer. |
| 2. | a large public room or hall adjacent to a legislative chamber. |
| 3. | a group of persons who work or conduct a campaign to influence members of a legislature to vote according to the group's special interest. |
| 4. | to solicit or try to influence the votes of members of a legislative body. |
| 5. | to try to influence the actions of (public officials, esp. legislators). |
| 6. | to urge or procure the passage of (a bill), by lobbying. |

A group whose members share certain goals and work to bring about the passage, modification, or defeat of laws that affect these goals. Lobbies (also called interest groups or pressure groups) can be long-standing (such as minority groups struggling to have their civil rights guaranteed) or ad hoc (such as a community threatened by proposed construction of a nuclear power plant). Lobbies may use grassroots methods, such as local rallies and campaigns, to build support for their cause and often employ professional lobbyists, who testify before congressional committees and approach policymakers in all government branches. Powerful lobbies, such as the AFL-CIO and the American Legion, with millions of members, have succeeded in establishing influence in Washington, D.C.