Definition of antediluvial in English:



  • 1Existing or occurring before the Flood described in the biblical book of Genesis, or (in later use) before a widespread flood as described in other mythological traditions; of or relating to the period before such a flood.

  • 2Geology. Earlier or older than a period of deposition of diluvial or drift deposits. Now chiefly historical.

  • 3Of animals, plants, etc.: prehistoric; long extinct; such as are known only from their fossil remains.

  • 4Very antiquated; ridiculously old-fashioned or out-of-date; = "antediluvian". Now somewhat rare.


Early 18th century; earliest use found in Edward Tyson (1651–1708), physician and anatomist. From ante- + diluvial, probably as alteration of antediluvian.