synchronism vs synchronicity

synchronism and synchronicity both are nouns.

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

As nouns, synchronism and synchronicity are synonyms defined as:

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

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

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