say it: sing-kruh-NIS-i-tee
synchronicity is a noun meaning "the relation that exists when things occur at the same time". It carries one recorded sense.
the relation that exists when things occur at the same time
“the drug produces an increased synchrony of the brain waves”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for synchronicity come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.