[ ee-ther ]
/ ˈi θər /


Also called diethyl ether, diethyl oxide, ethyl ether, ethyl oxide, sulfuric ether. Chemistry, Pharmacology. a colorless, highly volatile, flammable liquid, C4H10O, having an aromatic odor and sweet, burning taste, derived from ethyl alcohol by the action of sulfuric acid: used as a solvent and, formerly, as an inhalant anesthetic.
Chemistry. (formerly) one of a class of compounds in which two organic groups are attached directly to an oxygen atom, having the general formula ROR.
the upper regions of space; the clear sky; the heavens.
the medium supposed by the ancients to fill the upper regions of space.
Physics. a hypothetical substance supposed to occupy all space, postulated to account for the propagation of electromagnetic radiation through space.
Also ae·ther (for defs 3–5).

Origin of ether

1350–1400; Middle English < Latin aethēr the upper air, pure air, ether < Greek aithḗr, akin to aíthein to glow, burn, Old English ād funeral pyre, Latin aestus heat

Related forms

e·ther·ic [ih-ther-ik, ih-theer-] /ɪˈθɛr ɪk, ɪˈθɪər-/, adjectivesu·per·e·ther, noun

Can be confused

either ether Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ether

British Dictionary definitions for ether


/ (ˈiːθə) /


Also called: diethyl ether, ethyl ether, ethoxyethane a colourless volatile highly flammable liquid with a characteristic sweetish odour, made by the reaction of sulphuric acid with ethanol: used as a solvent and anaesthetic. Formula: C 2 H 5 OC 2 H 5
any of a class of organic compounds with the general formula ROR′ where R and R′ are alkyl groups, as in diethyl ether C 2 H 5 OC 2 H 5
the ether the hypothetical medium formerly believed to fill all space and to support the propagation of electromagnetic waves
Greek myth the upper regions of the atmosphere; clear sky or heaven
a rare word for air

Also (for senses 3–5): aether

Derived Forms

etheric (iːˈθɛrɪk), adjective

Word Origin for ether

C17: from Latin aether, from Greek aithēr, from aithein to burn
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medicine definitions for ether


[ ēthər ]


Any of a class of organic compounds in which two hydrocarbon groups are linked by an oxygen atom.
An anesthetic ether, especially diethyl ether.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for ether


[ ēthər ]

An organic compound in which two hydrocarbon groups are linked by an oxygen atom, having the general structure ROR, where R and R are the two hydrocarbon groups. At room temperature, ethers are pleasant-smelling liquids resembling alcohols but less dense and less soluble in water. Ethers are part of many naturally occurring organic compounds, such as starches and sugars, and are widely used in industry and in making pharmaceuticals.
A colorless, flammable liquid used as a solvent and formerly used as an anesthetic. Ether consists of two ethyl groups joined by an oxygen atom. Also called diethyl ether, ethyl ether. Chemical formula: C4H10O.
A hypothetical medium formerly believed to permeate all space, and through which light and other electromagnetic radiation were thought to move. The existence of ether was disproved by the American physicists Albert Michelson and Edward Morley in 1887.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.