Finnish word kaksonen comes from Proto-Uralic *kakta (Two.)
| Dictionary entry | Language | Definition |
|---|---|---|
| *kakta | Proto-Uralic (urj-pro) | Two. |
| *kakci | Proto-Finnic (fiu-fin-pro) | Two. |
| kaksi | Finnish (fin) | Two. |
| kaksonen | Finnish (fin) | A twin.. When used as modifier in compound terms appears in the form kaksois- and its English equivalents are adjectives twin, double, binary and dual. |