E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Bolt from the Blue (A).
There fell a bolt from the blue. A sudden and wholly unexpected catastrophe or event occurred, like a “thunderbolt” from the blue sky, or flash of lightning without warning and wholly unexpected.
1
“Namque Diespiter
Igni corusco nubila dividens,
Plerumque, per purum tonantes
Egit equos volucremque currum… .”
Horace: 1 Ode xxxiv. 5, etc.
“On Monday, Dec. 22nd [1890], there fell a bolt from the blue. The morning papers announced that the men were out [on strike].”—Nineteenth Century, February, 1891, p. 240.
In this phrase the word “bolt” is used in the popular sense for lightning, the Latin fulmen, the French foudre and tonnerre, in English sometimes for an aerolite. Of course, in strict scientific language, a flash of lightning is not a thunderbolt. Metaphorically, it means a sudden and wholly unexpected catastrophe, like a thunderbolt [flash of lightning] from a blue or serene sky.
2
German: Wie ein Blitzstrahl aus blauem Aether.
Italian: Comme un fulmine a ciel sereno.
Latin: Audiit et cœli genitor de parte serena intonuit hævum. (Virgil: Æneid, ix. 630.)
In this phrase the word “bolt” is used in the popular sense for lightning, the Latin fulmen, the French foudre and tonnerre, in English sometimes for an aerolite. Of course, in strict scientific language, a flash of lightning is not a thunderbolt. Metaphorically, it means a sudden and wholly unexpected catastrophe, like a thunderbolt [flash of lightning] from a blue or serene sky.
