muscle fiber vs somatic cell

muscle fiber and somatic cell both are nouns.

Word	Noun	Adjective	Verb	Adverb
muscle fiber	Yes	No	No	No
somatic cell	Yes	No	No	No

As nouns, somatic cell is a hypernym of muscle fiber; that is, somatic cell is a word with a broader meaning than muscle fiber:

muscle fiber: an elongated contractile cell that forms the muscles of the body
somatic cell: any of the cells of a plant or animal except the reproductive cells; a cell that does not participate in the production of gametes

Other hypernyms of muscle fiber include fiber, fibre, vegetative cell.

muscle fiber (noun)	somatic cell (noun)
an elongated contractile cell that forms the muscles of the body	any of the cells of a plant or animal except the reproductive cells; a cell that does not participate in the production of gametes