lobby is a word of English origin and it means "anteroom" or "Hall", in the literal translation into Portuguese.
However, this term is commonly used for designate a group of people, physical or legal, that organize themselves around a common goal and try to interfere in the decisions of the executive and legislative branches. so that these coincide with your interests.
You lobbies, also known as pressure groups, are very common in the political sphere. Theoretically, they are seen as a way to debate and communicate the interests of certain social groups or interests to parliamentarians or government executives.
When used in a transparent and healthy way, the lobby it can be an important tool that guarantees the civil and political rights of social groups.
Indeed, it is among the duties of the citizen to actively influence and participate in the decisions of the legislative, ensuring a balance and a better quality of life for all social classes and economic conditions in the country.
the members of a lobby are known for lobbyists, that is, the one who does the lobby.
See also the meaning of lobbyist.
Lobby in Brazil
In Brazil the lobby it gained an intense pejorative connotation, due to involvement with corruption, blackmail and other illicit pressure mechanisms practiced by politicians and big businessmen.
The private and selfish interests of these lobbies they harm the population in general, as they are exclusively aimed at the interests of political groups.
Another perverse way is the acceptance of bribes, given by pressure groups, so that their private interests are met, without the establishment of a public debate where the interested population has the opportunity to to intervene.
See also the meaning of Clique.