alkyl vs methyl radical

alkyl and methyl radical both are nouns.

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

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

alkyl: any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons
methyl radical: the univalent radical CH3- derived from methane

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

alkyl (noun)	methyl radical (noun)
any of a series of univalent groups of the general formula CnH2n+1 derived from aliphatic hydrocarbons	the univalent radical CH3- derived from methane