How do you name epoxides and ethers?

Hint:In order to name epoxides and ethers firstly the classify the compounds, a compound in which two carbon atoms are connected to an oxygen atom likewise epoxides are the three membered, cyclic compounds. Also all ethers will also have a similar common name, which is often used as with the IUPAC name. If we want to acquire the common name, we have to name the two groups flanking the $O$ atom in an alphabetized form and the word "ether" is added along with that.

Complete answer:
There are several ways of naming epoxides and ethers. In which epoxides is classified by two ways naming:
Substitutive names:These compounds we named as an alkane with an alkoxy alkane. Example \[{{\left( C{{H}_{3}} \right)}_{2}}CH-O-C{{H}_{3}}\] is \[2-methoxypropane\]
Functional class names:\[R-O-R'\] is named with the names of $R$ and \[R'\] in alphabetical order, followed by the class name "ether". Example \[{{\left( C{{H}_{3}} \right)}_{2}}CH-O-C{{H}_{3}}\] is ethyl isopropyl ether.
Also ethers is naming classified by-
Substitutive names:The compound is named as an alkene with an epoxy substituent. Example, \[1,2-epoxybutane\]

Functional class names:The compound is named as an epoxide of the corresponding alkene. Example, \[1,2-epoxybutane\] is also named as \[but-1-ene\text{ }epoxide\]
The Hantzsch Widman name:Here the ring we had named as a cyclopropane in which the $O$ atom replaces a $C{{H}_{2}}$ group indicated by the prefix "oxa" with the "a" which is being dropped when followed by a vowel. The three membered saturated ring is indicated by the prefix "ir" followed by the suffix "ane".
Therefore, \[1,2-epoxybutane\] is called ethyloxirane. The O atom is automatically number $1$ , so the ethyl group is on $C-2$ . We have no locating number is necessary here, because there is no such compound as \[3-ethyloxirane\]
Oxide of the Correspondent alkene:Examples are ethylene oxide and propylene oxide. The first three methods are accepted by IUPAC.
The fourth is used only for simple alkenes such as ethylene, propylene, and butylene.

Note:Also note that thiols are compounds that are structurally identical to alcohols except that they replace the oxygen atom in the hydroxyl group with a sulfur atom. Likewise, sulfides are structurally identical to ethers, but they replace the oxygen atom with a sulfur atom, as shown below.