beta decay vs radioactive decay

beta decay and radioactive decay both are nouns.

Word	Noun	Adjective	Verb	Adverb
beta decay	Yes	No	No	No
radioactive decay	Yes	No	No	No

As nouns, radioactive decay is a hypernym of beta decay; that is, radioactive decay is a word with a broader meaning than beta decay:

beta decay: radioactive decay of an atomic nucleus that is accompanied by the emission of a beta particle
radioactive decay: the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation

Other hypernyms of beta decay include decay, disintegration.

beta decay (noun)	radioactive decay (noun)
radioactive decay of an atomic nucleus that is accompanied by the emission of a beta particle	the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation