dekametre vs dekameter

dekametre and dekameter both are nouns.

Word	Noun	Adjective	Verb	Adverb
dekametre	Yes	No	No	No
dekameter	Yes	No	No	No

As nouns, dekametre and dekameter are synonyms defined as:

Other synonyms of dekametre include dam, decameter, decametre, dkm.

dekametre (noun)	dekameter (noun)
a metric unit of length equal to ten meters	a metric unit of length equal to ten meters