A cyclic ether is an ether in which oxygen replaces one or more carbons. Ethers are compounds with two alkyl or aryl groups bonded to an oxygen atom. Cyclic ethers are also known as heterocycles.
When applying a nomenclature system to cyclic ethers, IUPAC or historic naming may be used. Cyclic ethers are often referred to by their common names. Historically, they have been known as epoxides. The IUPAC system uses the name "oxirane" when naming them. To name a cycle ether using the historic method, take the longest chain, and name it as an alkene. Then, add the suffix "-oxide" to the end.