free electron vs negatron

free electron and negatron both are nouns.

Word	Noun	Adjective	Verb	Adverb
free electron	Yes	No	No	No
negatron	Yes	No	No	No

As nouns, negatron is a hypernym of free electron; that is, negatron is a word with a broader meaning than free electron:

free electron: electron that is not attached to an atom or ion or molecule but is free to move under the influence of an electric field
negatron: an elementary particle with negative charge

Other hypernyms of free electron include electron.

free electron (noun)	negatron (noun)
electron that is not attached to an atom or ion or molecule but is free to move under the influence of an electric field	an elementary particle with negative charge