| 1 | English | eth- | Used as a combining form to denote the presence... |
| 2 | English | ethyl | The univalent hydrocarbon radical, CH, formally... |
| 3 | Ancient Greek | Αἰθήρ | Upper Air |
| 4 | Ancient Greek | αἴθω | To ignite, kindle, light; To burn, blaze |
| 5 | Proto-Hellenic | *áitʰō | — |