gerontocracyPronunciation: /ˌdʒɛrənˈtɒkrəsi/Definition of gerontocracy noun a state, society, or group governed by old people. [mass noun] government based on rule by old people. Derivatives gerontocratPronunciation: /dʒɛˈrɒntəkrat/ noun gerontocraticPronunciation: /-ˈkratɪk/ adjective Origin: mid 19th century: from Greek gerōn, geront- 'old man' + -cracygerontocracy in other Oxford dictionaries Definition of gerontocracy in the US English dictionary