synchronism vs synchroneity

synchronism and synchroneity both are nouns.

Word	Noun	Adjective	Verb	Adverb
synchronism	Yes	No	No	No
synchroneity	Yes	No	No	No

As nouns, synchronism and synchroneity are synonyms defined as:

synchronism and synchroneity: the relation that exists when things occur at the same time

Other synonyms of synchronism include synchronicity, synchronisation, synchronization, synchronizing, synchrony.

synchronism (noun)	synchroneity (noun)
the relation that exists when things occur at the same time	the relation that exists when things occur at the same time