intermittence vs intermittency

intermittence and intermittency both are nouns.

Word	Noun	Adjective	Verb	Adverb
intermittence	Yes	No	No	No
intermittency	Yes	No	No	No

As nouns, intermittence and intermittency are synonyms defined as:

intermittence and intermittency: the quality of being intermittent; subject to interruption or periodic stopping

intermittence (noun)	intermittency (noun)
the quality of being intermittent; subject to interruption or periodic stopping	the quality of being intermittent; subject to interruption or periodic stopping