In the IUPAC Nomenclature system, ethers are named using the general formula "alkoxyalkane", for example CH–CH–O–CH is methoxyethane. If the ether is part of a more-complex molecule, it is described as an alkoxy substituent, so –OCH would be considered a "methoxy-" group. The simpler alkyl radical is written in front, so CH–O–CHCH would be given as methoxy(CHO)ethane(CHCH).