Definition of "doomsday"

The day when God is expected to judge the world; the end times.  examples

Judgement day; the day of the Final Judgment; any day of decisive judgement or final dissolution.  examples

Any day of great death and destruction; end of the world; an apocalypse.  examples

Any of the memorable dates used in the doomsday rule for computing weekdays from dates.  examples

Concerned with or predicting future universal destruction.  examples

Given to or marked by forebodings or predictions of impending calamity.  quotations  examples

Capable of causing widespread or total destruction.  examples