Branched cyclohexanes:

Cycloalkanes containing a cycloalkane moiety related to an alkane moiety are generally named like that the cycloalkane is the parent system and the alkane moiety is referred to be an alkyl substituent. Hence, the structure in Diagram is methylcyclohexane and not cyclohexylmethane. Note that there is no requirement to number the cycloalkane ring while only one substituent is present.

Figure:  (a) Methylcyclohexane; (b) 1-cyclohexyloctane; (c) 1-ethyl-3-methylcyclohexane.

If the alkane moiety consists of more carbon atoms than the ring, the alkane moiety turns into the parent system and the cycloalkane group becomes the substituent. For instance, the structure in Figure is termed as 1-cyclohexyloctane and not butylcyclohexane. In this case, numbering is essential to identify the position of the cycloalkane on the alkane chain.