1. A pleasant-smelling colourless volatile liquid that is highly flammable. It is used as an anaesthetic and as a solvent or intermediate in industrial processes.
2. Any organic compound with a similar structure to the ether, having an oxygen atom linking two alkyl or other organic groups.
3. The clear sky; the upper regions of air beyond the clouds.
4. A very rarefied and highly elastic substance formerly believed to permeate all space, including the interstices between the particles of matter, and to be the medium whose vibrations constituted light and other electromagnetic radiation.
Plural Noun: Ethers
Ether is highly flammable.