Where does “double flash” come from?

double flash (English) comes from English doublé, from French doublé, from Middle French double, from Old French doble, from Latin dūplus, from Proto-Italic *duplos — double.

double flash (English): The characteristic visual phenomenon produced by the atmospheric detonation of a nuclear weapon, consisting of a very brief, bright flash of light which dims rapidly, followed by a second, gradually brightening flash

Definitions

  1. The characteristic visual phenomenon produced by the atmospheric detonation of a nuclear weapon, consisting of a very brief, bright flash of light which dims rapidly, followed by a second, gradually brightening flash

Ancestry of “double flash”, step by step

double flash traces back through two separate lines of ancestry.

via English doublé

StepLanguageWordMeaning
1EnglishdoubléA compound attack that deceives the opponent's...
2Frenchdoublédouble, brace, pair; double; doublé
3Middle Frenchdouble—
4Old Frenchdobledouble
5Latindūplusdouble (twice as much, or as big)
6Proto-Italic*duplosdouble

via English Flash

StepLanguageWordMeaning
1EnglishFlashA multimedia platform, most often used for adding animation and interactivity to webpages
2Middle Englishflasshen—
Every word from Proto-Italic *duplos →