Rule 1. Ethers can be named as alkoxy derivatives of alkanes (substitutive IUPAC nomenclature). The longest chain is taken as the main chain and the alkoxide is named as a substituent.

Rule 2. Functional nomenclature (IUPAC) names ethers as derivatives of two alkyl groups, arranged alphabetically, ending the name in the word ether.
Rule 3. Cyclic ethers are formed by substituting -CH2- for -O- in a cycle. The numbering begins with oxygen and they are named with the prefix oxa- followed by the name of the cycle.
