cubic metre vs cubic meter

cubic metre and cubic meter both are nouns.

Word	Noun	Adjective	Verb	Adverb
cubic metre	Yes	No	No	No
cubic meter	Yes	No	No	No

As nouns, cubic metre and cubic meter are synonyms defined as:

cubic metre and cubic meter: a metric unit of volume or capacity equal to 1000 liters

Other synonyms of cubic metre include kiloliter, kilolitre.

cubic metre (noun)	cubic meter (noun)
a metric unit of volume or capacity equal to 1000 liters	a metric unit of volume or capacity equal to 1000 liters