British spelling vs muscle fibre

British spelling and muscle fibre both are nouns.

Word	Noun	Adjective	Verb	Adverb
British spelling	Yes	No	No	No
muscle fibre	Yes	No	No	No

British spelling (noun)	muscle fibre (noun)
English orthography used in the UK, Ireland and most of the Commonwealth (characterized by 'analyse', 'centre' and 'useable')	an elongated contractile cell that forms the muscles of the body