A council was a group of people who came together to discuss, deliberate and vote on certain matters. The place set aside for these meetings was usually referred to as the council chamber. A person who served on a council usually held the title of councilor.
In the ten years following the assassination of Klingon Emperor Reclaw, the Empire was ruled by a council elected by the people, an era referred to as "The Dark Time" by Klingon historians. By the mid-22nd century into late-24th century, the Empire was ruled by the Klingon High Council whose members represented the most powerful of the Klingon Houses. (DS9: "You Are Cordially Invited", ENT: "Broken Bow", TNG: "Sins of The Father") The Klingon Oversight Council was a body of the Klingon Defense Forces that approved Klingons to become officers. (DS9: "Once More Unto the Breach")
The Detapa Council was the civilian governing body of the Cardassian Union. Formed in the 19th century, the council was technically in control of the Central Command and the Obsidian Order but in reality, the Council had virtually no powers to control the military arm. The Council was presided over by a Chairman. It was overthrown in mid-2373, when the Cardassian Union joined the Dominion. (DS9: "Cardassians", "Defiant", "Return to Grace", "By Inferno's Light")
The Xindi Council meets in 2153
The Xindi Council was founded as an alliance between the five surviving Xindi species following the Xindi Civil War in the mid-21st century. The Council's primary mission was to find a new homeworld for the Xindi, after the destruction of Xindus in the war. During the Xindi incident of 2153, the council convened to discuss the use of a weapon against the planet Earth. (ENT: "The Xindi", "Stratagem", "The Council")
A city council was a type of city government on 20th century Earth. (TOS: "The City on the Edge of Forever"; Star Trek IV: The Voyage Home)
The Vulcan Science Council was an agency of the Vulcan High Command during the 22nd century. (ENT: "Fallen Hero")
The Organian Council of Elders was a council of wise men on the planet Organia. The Council was not a governing body, since the Organians did not have leaders. (TOS: "Errand of Mercy")
The Eminian High Council, also known as the High Council of Eminiar, was the governing body of the Eminian Union and the planet Eminiar VII in 2267. (TOS: "A Taste of Armageddon")
The Halkan Council was a government entity of the Halkan species in the late-23rd century. The council had the authority to conduct diplomacy and make trade agreements with foreign powers. (TOS: "Mirror, Mirror")
On Amerind, it was against custom to interrupt a tribal elder at council, even for a medicine chief. (TOS: "The Paradise Syndrome")
The Gideon Council was a governing body of the planet Gideon during the late-23rd century. (TOS: "The Mark of Gideon")
A meeting of the Federation Council in 2286
The Federation Council was the unicameral legislature of the United Federation of Planets. Seats on the Council were filled by representatives from the various Federation members. In 2286, the Council convened in San Francisco. (TOS: "Amok Time"; DS9: "Rapture"; VOY: "In the Flesh"; Star Trek IV: The Voyage Home) The Federation Archaeology Council was a Federation organization of archaeologists. (TNG: "Qpid") Similarly, the Daystrom Institute Archaeological Council was a council attached to the Daystrom Institute that dealt with matters of archaeology. (DS9: "Q-Less")
The Elysian Ruling Council was the governing body of Elysia, a pocket universe in the Delta Triangle inhabited by representatives of 123 races, the existence of which dated back more than a thousand years as of 2269. (TAS: "The Time Trap")
A council on Ventax II drew up a constitution which was later ratified by the population of the planet. (TNG: "Devil's Due")
The Volan Colonies Council was a group of representatives that met to discuss matters affecting the Volan colonies. In 2370, the council met on Volan III following the Federation decision to cede the planet to the Cardassian Union. (DS9: "The Maquis, Part I", "The Maquis, Part II")
After the Dominon captured the space station Deep Space 9 in 2373, a Ruling Council of three members was established to oversee the day-to-day matters concerning station life. It initially comprised Weyoun 5 and Gul Dukat but Constable Odo was later asked to sit on the council. (DS9: "A Time to Stand")