Coincidence
early 17th century (in the sense ‘occupation of the same space’): from medieval Latin coincidentia, from coincidere ‘coincide, agree’ (see coincide).
wiktionary
From French coïncidence.
Morphologically coincide + -ence.
etymonline
coincidence (n.)
c. 1600, "exact correspondence in substance or nature," from French coincidence, from coincider, from Medieval Latin coincidere, literally "to fall upon together," from assimilated form of Latin com "with, together" (see com-) + incidere "to fall upon" (from in- "upon" + combining form of cadere "to fall," from PIE root *kad- "to fall").
From 1640s as "occurrence or existence during the same time." Meaning "a concurrence of events with no apparent connection, accidental or incidental agreement" is from 1680s, perhaps first in writings of Sir Thomas Browne.
