Catalan word on comes from Proto-Indo-European *kʷe-, Proto-Indo-European *kʷo-, and later Proto-Italic *kʷis (Who, what (interrogative).)
| Dictionary entry | Language | Definition |
|---|---|---|
| *kʷe- | Proto-Indo-European (ine-pro) | |
| *kʷo- | Proto-Indo-European (ine-pro) | |
| *kʷís | Proto-Indo-European (ine-pro) | Who, what (interrogative). Who, which, that (relative) Which, what. |
| *kʷis | Proto-Italic (itc-pro) | Who, what (interrogative). |
| unde | Latin (lat) | Whence, from where. |
| on | Catalan (cat) | Where. |