molecular weight vs relative molecular mass

molecular weight and relative molecular mass both are nouns.

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

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

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

molecular weight (noun)	relative molecular mass (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