Where does “ground zero” come from?

ground zero (English) comes from English zero, from Middle French zero, from Italian Zero, from New Latin zerum, from Medieval Latin zephirum, from Arabic صِفْر, from Sanskrit शून्य, from Proto-Indo-European ḱówH-.

ground zero (English): Originally, the point on the land or water surface below which a nuclear bomb detonates in the air; now also the point on such a surface at or above the detonation

Definitions

  1. Originally, the point on the land or water surface below which a nuclear bomb detonates in the air; now also the point on such a surface at or above the detonation

Ancestry of “ground zero”, step by step

ground zero traces back through two separate lines of ancestry.

via English zero

StepLanguageWordMeaning
1EnglishzeroThe cardinal number occurring before one and that...
2Middle Frenchzero
3ItalianZerozero
4New Latinzerum
5Medieval Latinzephirumzero
6Arabicصِفْرzero, nothing, empty, void; nothing, cipher;...
7Sanskritशून्यzero; cipher, cypher; blank, deserted
8Proto-Indo-EuropeanḱówH-

via English ground

StepLanguageWordMeaning
1EnglishgroundThe surface of the Earth, as opposed to the sky...
2Middle Englishgroundground; Earth
3Old Englishgrundground; bottom, foundation; abyss, depths
4Proto-Germanicgrunduzground, foundation
5Proto-Indo-Europeangʰrem-to be angry; to sound, bellow, growl, roar, be...
6Proto-Indo-Europeangʰer-to rub; to stroke; to grind
Every word from Proto-Indo-European ḱówH-Every word from Sanskrit शून्यEvery word from Arabic صِفْر