French word deux comes from Proto-Indo-European *dwó, Proto-Indo-European *dāu-, and later Proto-Italic *duō (Two.)
| Dictionary entry | Language | Definition |
|---|---|---|
| *dwó | Proto-Indo-European (ine-pro) | |
| *dāu- | Proto-Indo-European (ine-pro) | |
| *duō | Proto-Italic (itc-pro) | Two. |
| duellum | Old Latin (itc-ola) | |
| duo | Latin (lat) | Two; 2. |
| deuz | Old French (fro) | (two). |
| deux | Middle French (frm) | Two. |
| deux | French (fra) | Two (in the plural) twos. Two. |