synchronistic

UK: /ˌsɪŋkrəˈnɪstɪk/

Collins Concise English Dictionary © HarperCollins Publishers::

synchronistic / ˌsɪŋkrəˈnɪstɪk/, synchronistical / ˌsɪŋkrəˈnɪstɪkəl/ adjective

1. of, relating to, or exhibiting synchronism

ˌsynchroˈnistically adverb

WordReference Random House Unabridged Dictionary of American English © 2025

syn•chro•nism  (sing′krə niz′əm), n. 

1. coincidence in time;
   contemporaneousness;
   simultaneousness.
2. the arrangement or treatment of synchronous things or events in conjunction, as in a history.
3. a tabular arrangement of historical events or personages, grouped according to their dates.
4. Electricity, Physics [Physics, Elect.] the state of being synchronous.
5. Psychiatry the simultaneous occurrence of causally unrelated events and the belief that the simultaneity has meaning beyond mere coincidence.

• Greek synchronismós, equivalent. to sýnchron(os) synchronous + -ismos -ism
• Medieval Latin synchronismus
• 1580–90

syn′chro•nis′tic, syn′chro•nis′ti•cal, adj. 
syn′chro•nis′ti•cal•ly, adv.