devolvement vs devolution

devolvement and devolution both are nouns.

Word	Noun	Adjective	Verb	Adverb
devolvement	Yes	No	No	No
devolution	Yes	No	No	No

As nouns, devolvement and devolution are synonyms defined as:

devolvement and devolution: the delegation of authority (especially from a central to a regional government)

devolvement (noun)	devolution (noun)
the delegation of authority (especially from a central to a regional government)	the delegation of authority (especially from a central to a regional government)
	the process of declining from a higher to a lower level of effective power or vitality or essential quality