The attempt to influence government officials, elected and otherwise, to secure a favourable decision on a public policy or a political appointment.
(Malcolmson, Patrick and Richard Myers. 2005. The Canadian Regime: An Introduction to Parliamentary Government in Canada, 3rd ed. Peterborough, ON: Broadview Press p. 191.)
This concept has become increasingly defined in law through legislation governing the registration and the conduct of lobbying.
Details can be found on government web sites. For example, the Office of the Commissioner of Lobbying of Canada included the following in its June 2008 document on the Summary of New Requirements:
"The Lobbying Act defines activities that, when carried out for compensation, are considered to be lobbying. These activities are detailed in the Lobbying Act. Generally speaking, they include communicating with public office holders with respect to changing federal laws, regulations, policies or programs, obtaining a financial benefit such as a grant or contribution, in certain cases, obtaining a government contract, and in the case of consultant lobbyists (see below), arranging a meeting between a public office holder and another person. Public office holders include employees of the federal public service, Members of Parliament, Senators and many others in government. The Lobbying Act provides exemptions for certain types of communication, such as simple requests for information, and for certain individuals, such as members of another level of government in Canada."