Where does “deux-mille” come from?

deux-mille (French) comes from French mille, from Middle French mille, from Old French mile, from Latin Mīlle, from Proto-Italic smīɣeslī, from Proto-Indo-European smih₂ǵʰéslih₂.

Ancestry of “deux-mille”, step by step

deux-mille traces back through two separate lines of ancestry.

via French mille

StepLanguageWordMeaning
1Frenchmillethousand, a thousand, one thousand; thousand;...
2Middle Frenchmillethousand
3Old Frenchmileone thousand
4LatinMīllethousand; 1000
5Proto-Italicsmīɣeslīthousand
6Proto-Indo-Europeansmih₂ǵʰéslih₂—

via French deux

StepLanguageWordMeaning
1Frenchdeuxtwo; twos
2Middle Frenchdeuxtwo
3Old Frenchdeux—
Every word from Proto-Indo-European smih₂ǵʰéslih₂ →Every word from Proto-Italic smīɣeslī →Every word from Latin Mīlle →