radiation vs emission

radiation and emission both are nouns.

Word	Noun	Adjective	Verb	Adverb
radiation	Yes	No	No	No
emission	Yes	No	No	No

As nouns, emission is a hypernym of radiation; that is, emission is a word with a broader meaning than radiation:

Other hypernyms of radiation include emanation.

As nouns, emission is a hypernym of radiation; that is, emission is a word with a broader meaning than radiation:

radiation: the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay
emission: the release of electrons from parent atoms

radiation (noun)	emission (noun)
the act of spreading outward from a central source	the act of emitting; causing to flow forth
(medicine) the treatment of disease (especially cancer) by exposure to a radioactive substance	the occurrence of a flow of water (as from a pipe)
a radial arrangement of nerve fibers connecting different parts of the brain	the release of electrons from parent atoms
the spread of a group of organisms into new habitats	any of several bodily processes by which substances go out of the body
energy that is radiated or transmitted in the form of rays or waves or particles	a substance that is emitted or released
the spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay
syndrome resulting from exposure to ionizing radiation (e.g., exposure to radioactive chemicals or to nuclear explosions); low doses cause diarrhea and nausea and vomiting and sometimes loss of hair; greater exposure can cause sterility and cataracts and some forms of cancer and other diseases; severe exposure can cause death within hours