(figuratively) A person or organisation that seemingly acts like a machine, being particularly efficient, single-minded, or unemotional.
Especially, the group that controls a political or similar organization; a combination of persons acting together for a common purpose, with the agencies which they use.
Supernatural agency in a poem, or a superhuman being introduced to perform some exploit.
(politics) The system of special interest groups that supports a political party, especially in urban areas.