Jung’s definitions of synchronicity

From
Religion, Science and Synchronicity
Dr. Roderick Main

Jung was in his mid-seventies before he formally set down his thoughts about synchronicity – although he had been thinking about and occasionally alluding to the phenomenon for almost thirty years….

Most succinctly, he defined synchronicity as “meaningful coincidence,” as “
” acausal parallelism” or an “acausal connecting principle.”

More fully, he described it as “the simultaneous occurrence of a certain psychic state with one or more external events which appear as meaningful parallels to the momentary subjective state.” (Full article and source of quotations)