Illustrated Glossary of Organic Chemistry

Ether: (1) A functional group characterized by an oxygen atom single-bonded to two carbon atoms. The carbon atoms may be of any hybridization, but cannot be carbonyl groups. The term may also describe a molecule containing this functional group.

Generic ether structure    
 Chloromethyl phenyl ether

(2) Ethyl ether (also called diethyl ether); CH3CH2OCH2CH3. Sometimes abbreviated as Et2O. A common nonpolar (ε = 4.3), aprotic solvent. Tetrahydrofuran (THF) is another common ether solvent.

Diethyl ether    
Tetrahydrofuran (THF)