A lobby is a collective with common interests that carries out actions aimed at influencing the Public Administration to promote decisions favorable to the interests of that particular sector of society. The first political uses of this term are from the 19th century.
Already in 1830 the word lobby designated the corridors of the British House of Commons where pressure groups could come to discuss with members of Parliament. Also during the American Civil War, General Grant, after the White House fire, settled in the low lobby of a hotel, which soon became full of lobbyists. In principle, the activity of the lobby is legal, and brings before the political power the opinions and interests of those involved in the decisions of public authorities.
Lobbying has a long tradition in the United States, where its practice has been understood as a necessary collaboration between society and public authorities for the effective exercise of politics.