fiber bundle vs fibre bundle

fiber bundle and fibre bundle both are nouns.

Word	Noun	Adjective	Verb	Adverb
fiber bundle	Yes	No	No	No
fibre bundle	Yes	No	No	No

As nouns, fiber bundle and fibre bundle are synonyms defined as:

fiber bundle and fibre bundle: a bundle of fibers (especially nerve fibers)

Other synonyms of fiber bundle include fascicle, fasciculus.

fiber bundle (noun)	fibre bundle (noun)
a bundle of fibers (especially nerve fibers)	a bundle of fibers (especially nerve fibers)