Junta
A junta (hoon-tuh) is a governing administrative council. It can consist of civilian and/or military officers holding power in a country, especially after a coup d'état. In socialist regimes it is often referred to as a politburo. In Islamic cultures it is often referred as a Majlis al-Shura. As a general rule juntas are not democratically elected, lack a system of checks and balances, and tend to be authoritarian ruling by diktat.
Many dictators have come to power at the head of a junta. An example of a junta presently in power is that ruling Burma.
Small select (or self-selected) groups of people in power in other contexts may also be referred to as juntas, the term generally denoting that power has been illegitimately acquired and/or is unjustly exercised. An example of such a junta (or cabal) is the Wikipedia police.
The word junta is Spanish for a council or committee, which is derived from the Latin junctus, meaning joined.