Where does “quinquadecillion” come from?

quinquadecillion (English) comes from English decillion, from English -illion, from English million, from Middle English milioun, from Middle French million, from Old French millon, from Italian milione, from Italian mille.

Ancestry of “quinquadecillion”, step by step

quinquadecillion traces back through two separate lines of ancestry.

via English decillion

StepLanguageWordMeaning
1Englishdecillion10
2English-illionCombined with Latin prefixes for names of...
3EnglishmillionThe cardinal number 1,000,000: 10; a thousand...
4Middle EnglishmiliounThe cardinal number 1 000 000: 106; a thousand thousand
5Middle Frenchmillionmillion, 10
6Old Frenchmillon
7Italianmilionemillion
8Italianmillethousand
9LatinMīllethousand; 1000
10Proto-Italicsmīɣeslīthousand
11Proto-Indo-Europeansmih₂ǵʰéslih₂

via English quinqua

StepLanguageWordMeaning
1Englishquinqua
Every word from Proto-Indo-European smih₂ǵʰéslih₂Every word from Proto-Italic smīɣeslīEvery word from Latin Mīlle