saeculum

noun4

1. •
   An approximately 85-year cycle in Strauss-Howe generational theory, a highly controversial sociological theory that postulates that zeitgeist and popular cultural values exist along recurring cycles.
2. •
   (historical) A cyclical period of time, roughly equal to the time needed for the complete renewal of a human population.
3. •
   (historical) Any of a sequence of ages (periods of time) such that each age ends with the death of the last person remaining alive since its beginning, and the end of an age marks the beginning of the next.

   • According to legend, the gods had allotted a certain number of saecula to every people or civilization; the Etruscans, for example, had been given ten saecula.
4. •
   (historical) Any of a sequence of ages of set length, used to periodise chronicles and track wars.

   • At the time of the reign of emperor Augustus, the Romans decided that a saeculum was 110 years.