Government by a technologically superior elite.
In most cases the use of the term technocracy is limited to the use of advanced technology by a group or faction of modosophonts to establish dominance or control over another, less-advanced group. For example a mostly primitive or middle tech polity may be ruled by a high tech elite, or a society enabled with high-tech could be ruled by an ultratech elite.
Often the administrators of a particular polity are significantly more technologically advanced then the citizens under them, so technocracy is a common form of government throughout the Civilized Galaxy. If a technocracy uses artificial intelligence to facilitate their rule, the technocracy becomes an aiocracy.
Societies which are ruled or guided by archailect-level intelligences are known as archailectocracies; such cultures are very common in the Terragen civilisation, especially in the Inner Sphere and Middle Regions.