nanometre vs micromillimeter

nanometre and micromillimeter both are nouns.

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

As nouns, nanometre and micromillimeter are synonyms defined as:

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

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

nanometre (noun)	micromillimeter (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