duodecimvirate
A group of twelve people, especially (politics) a council of twelve men sharing office or rule, particularly such groups of magistrates in ancient Rome.
uncommon
Strabo ſeems to ſay, there were fronting theſe halls, (which Diodorus likewiſe ſeems to diſtinguiſh from the labyrinth, ſtyling it the work of the Duodecimvirate) 27 other halls.
Where it comes from
From Latin duodecimvirātus, from duodecimvir + -ātus. Equivalent to duodecimvir + -ate (forms nouns denoting rank or office, here the group of people involved with it).
Adapted from the Wiktionary entry duodecimvirate (CC BY-SA 4.0).