1. belief in the imminent end of human history, to be followed by a thousand-year period of peace and blessedness (often associated with the Second Coming of Christ). Such beliefs were current in the early Christian church and appeared sporadically, primarily from the 11th through the 17th centuries, in periods of political or intellectual crisis and among marginalized groups. Some groups proclaim similar beliefs but without the language and imagery of Christianity.

2. by extension, any belief that rapid and violent change can lead to a golden age of justice and peace. —millenarian adj.