nanometer vs nanometre

nanometer and nanometre both are nouns.

Word	Noun	Adjective	Verb	Adverb
nanometer	Yes	No	No	No
nanometre	Yes	No	No	No

As nouns, nanometer and nanometre are synonyms defined as:

nanometer and nanometre: a metric unit of length equal to one billionth of a meter

Other synonyms of nanometer include micromillimeter, micromillimetre, millimicron, nm.

nanometer (noun)	nanometre (noun)
a metric unit of length equal to one billionth of a meter	a metric unit of length equal to one billionth of a meter