Ethers are compounds with two alkyl groups bonded to an oxygen atom. Ethers have the general formula R1-O-R2 where R1 and R2 are hydrocarbon groups. The difference between alcohol and ether are that in an alcohol, one hydrogen atom is replaced by an alkyl group. In an ether, however, both hydrogen atoms are replaced by alkyl groups.
Simple ethers can be named by naming the alkyl groups alphebetically followed by the word "ether". A more efficient way of naming ethers would be by adding -oxy- to the prefix for the smaller hydrocarbon group and joining it to the alkane name of the larger hydrocarbon group.
For example, CH3-O-CH2-CH3 would be called using this common name approach as Ethyl Methyl Ether and another way to name it would be methoxyethane. If just two alkyl groups are identical in its molecular formula, use the prefix di-, tri-, tetra-, etc to signify these branches. Eg. diethyl ether