# ether

> English word · Noun · IPA /ˈiː.θə/ · frequency rank #17,131

## Definitions
1. The substance formerly supposed to fill the upper regions of the atmosphere above the clouds, in particular as a medium breathed by deities.
2. The substance formerly supposed to fill the upper regions of the atmosphere above the clouds, in particular as a medium breathed by deities.
3. Often as aether and more fully as luminiferous aether: The hypothetical substance permeating space, functioning as a medium for electromagnetic waves to propagate through, and which does not exert resistance to the movement of matter; its existence is incompatible with Einstein's theory of relativity; famously found to be undetectable by the 1887 Michelson–Morley experiment.
4. The atmosphere or space as a medium for broadcasting radio and television signals; also, a notional space through which Internet and other digital communications take place; cyberspace.
5. A particular quality created by or surrounding an object, person, or place; an atmosphere, an aura.
6. Diethyl ether (C₄H₁₀O), an organic compound with a sweet odour used in the past as an anaesthetic.
7. Any of a class of organic compounds containing an oxygen atom bonded to two hydrocarbon groups.
8. Starting fluid.

## Etymology
From Middle English ēther (“the caelum aetherum of ancient cosmology in which the planets orbit; a shining, fluid substance described as a form of air or fire; air”), borrowed from Anglo-Norman ether and Middle French ether, ethere, aether, from Old French aether (“highest and purest part of the atmosphere; medium supposedly filling the upper regions of space”) (modern French éther), or directly from its etymon Latin aethēr (“highest and purest part of the atmosphere; air; heavens, sky; light of day; ethereal matter surrounding a deity”) (note also New Latin aethēr (“chemical compound analogous to diethyl ether”)), from Ancient Greek αἰθήρ (aithḗr, “purer upper air of the atmosphere; heaven, sky; theoretical medium supposed to fill unoccupied space and transmit heat and light”), from αἴθω (aíthō, “to burn, ignite; to blaze, shine”), from Proto-Indo-European *h₂eydʰ- (“to burn; fire”).
The English word is cognate with Italian ether, ethera (both obsolete), etere, Middle Dutch ether (modern Dutch aether (obsolete), ether), German Äther, Ether, Portuguese éter, Spanish éter.

## Easily confused with
- **ever** (https://plainspell.com/en/vs/ether-vs-ever)
- **ethic** (https://plainspell.com/en/vs/ether-vs-ethic)
- **ethos** (https://plainspell.com/en/vs/ether-vs-ethos)
- **ethyl** (https://plainspell.com/en/vs/ether-vs-ethyl)
- **Euler** (https://plainspell.com/en/vs/ether-vs-euler)
- **eth** (https://plainspell.com/en/vs/eth-vs-ether)
- **ECHR** (https://plainspell.com/en/vs/echr-vs-ether)
- **enter** (https://plainspell.com/en/vs/enter-vs-ether)
- **elder** (https://plainspell.com/en/vs/elder-vs-ether)
- **eager** (https://plainspell.com/en/vs/eager-vs-ether)
- **Ethan** (https://plainspell.com/en/vs/ethan-vs-ether)
- **eater** (https://plainspell.com/en/vs/eater-vs-ether)
- **Ethel** (https://plainspell.com/en/vs/ethel-vs-ether)
- **Elmer** (https://plainspell.com/en/vs/elmer-vs-ether)
- **ester** (https://plainspell.com/en/vs/ester-vs-ether)
- **ember** (https://plainspell.com/en/vs/ember-vs-ether)
- **ender** (https://plainspell.com/en/vs/ender-vs-ether)
- **either** (https://plainspell.com/en/vs/either-vs-ether)
- **Esther** (https://plainspell.com/en/vs/esther-vs-ether)
- **etched** (https://plainspell.com/en/vs/etched-vs-ether)

## Common misspellings (7)
`ehter`, `etehr`, `etherr`, `ethher`, `ethre`, `etther`, `teher`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/ether