Definition: Word of English origin which represents the act of acting on public decision in such a way as to influence, modify or influence it. Originally, the word "Lobby" means in English the anteroom, the corridor, the living room. In the United States, this corresponds to the anteroom that elected officials had to go through before going to the sessions of Congress. In the United Kingdom, it was the hallway leading to the House of Commons (and hence where influence was exercised). We have used the word "lobbying".
A lobbyist is a person who tries to influence, to influence the political decision.
Lobbying appears to be the art of influencing the decision-making of the public community, public authorities or decision-makers.