alkyl radical vs ethyl

alkyl radical and ethyl both are nouns.

Word	Noun	Adjective	Verb	Adverb
alkyl radical	Yes	No	No	No
ethyl	Yes	No	No	No

As nouns, ethyl is a hyponym of alkyl radical; that is, ethyl is a word with a more specific, narrower meaning than alkyl radical:

alkyl radical: any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons
ethyl: the univalent hydrocarbon radical C2H5 derived from ethane by the removal of one hydrogen atom

Other hyponyms of alkyl radical include ethyl group, ethyl radical, methyl, methyl group, methyl radical.

alkyl radical (noun)	ethyl (noun)
any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons	the univalent hydrocarbon radical C2H5 derived from ethane by the removal of one hydrogen atom