relative molecular mass vs molecular weight

relative molecular mass and molecular weight both are nouns.

Word	Noun	Adjective	Verb	Adverb
relative molecular mass	Yes	No	No	No
molecular weight	Yes	No	No	No

As nouns, relative molecular mass and molecular weight are synonyms defined as:

relative molecular mass and molecular weight: (chemistry) the sum of the relative atomic masses of the constituent atoms of a molecule

relative molecular mass (noun)	molecular weight (noun)
(chemistry) the sum of the relative atomic masses of the constituent atoms of a molecule	(chemistry) the sum of the relative atomic masses of the constituent atoms of a molecule