ether

noun

ˈē-thər 

1

a

: the rarefied element formerly believed to fill the upper regions of space

b

: the upper regions of space : heavens

2

a

: a light volatile flammable liquid C₄H₁₀O used chiefly as a solvent and especially formerly as an anesthetic

b

: any of a class of organic compounds characterized by an oxygen atom attached to two carbon atoms

3

a

or less commonly aether

ˈē-thər 

: a medium that in the wave theory of light permeates all space and transmits transverse waves

b

: airwaves

etheric

i-ˈther-ik 

-ˈthir-

adjective

Examples of ether in a Sentence

The balloon disappeared into the ether.

Recent Examples on the Web

The core, however, remains trading and custody, with bitcoin and ether comprising 88% of platform assets. —Marie Poteriaieva, Forbes.com, 9 Sep. 2025

While doctors have significantly refined their techniques over the subsequent 150 years—ether made patients throw up and was flammable enough to cause mid-surgery explosions—there are still outstanding questions about how anesthesia works. —Rj MacKenzie, Popular Science, 3 Sep. 2025

Solana, up 8% in 2025, still has a ways to go to catch up to blue-chip bitcoin and ether, which have gained 18% and 32%, respectively, this year. —Tanaya MacHeel, CNBC, 3 Sep. 2025

Flush with enthusiasm amid the bills’ imminent passage, investors have lifted the three major crypto tokens — bitcoin, ether and ripple — to all-time highs. —Rob Wile, NBC news, 18 July 2025

Word History

Etymology

Middle English, from Latin aether, from Greek aithēr, from aithein to ignite, blaze; akin to Old English ād pyre — more at edify

First Known Use

14th century, in the meaning defined at sense 1a

Phrases Containing ether

• diethyl ether
• ether extract
• ethyl ether
• into the ether
• over/through the ether
• the ether

Kids Definition

ether

noun

ˈē-thər 

1

a

: an invisible substance once believed to fill the upper regions of space

b

: the upper regions of space : heavens

2

: an easily evaporated flammable liquid used chiefly to dissolve other substances and especially formerly as an anesthetic

Medical Definition

ether

noun

ˈē-thər 

1

: a medium that in the wave theory of light permeates all space and transmits transverse waves

2

a

: a light volatile flammable liquid C₄H₁₀O used especially formerly chiefly as an anesthetic

called also diethyl ether, ethyl ether, ethyl oxide

b

: any of various organic compounds characterized by an oxygen atom attached to two carbon atoms