Crack of doom
The Crack of Doom is an old term used for the Christian Day of Judgement, referring in particular to the blast of trumpets signalling the end of the world in Chapter 8 of the Book of Revelation. A "crack" had the sense of any loud noise, preserved in the phrase "crack of thunder", and Doom was a term for the Last Judgement, as Doomsday still is.
- 'Why do you show me this? A fourth! Start, eyes!
- What, will the line stretch out to the crack of doom?
- Another yet! A seventh! I'll see no more:'
(Act 4, scene 1, 112–117)- meaning that Banquo's line will endure until the Judgement Day, flattery for King James I, who claimed descent from Banquo.
- OED, "Crack"