Alkyl groups - IUPAC System of Naming Organic Compounds
These groups involves one hydrogen atom less as compared to the alkane. These groups are named by substituting the suffix ane of the name of the subsequent alkane by yl. That is alkane - ane + yl = alkyl.
For example,
CH4 : Methane becomes
CH3- : Methyl
CH3 CH3 : Ethane becomes
CH3 CH2- : Ethyl
CH3 CH2 CH3 : Propane becomes
CH3 CH2 CH2 : Propyl etc.