Sometimes words just strike me as weird. Like, accident and incident both end in -cident…but what does that mean? Are they even connected? Or is it just another coincidence?
Oh, coincidence. That’s another one.
Accident showed up in the late fourteenth century actually meaning an event or incident (-_-). It comes from the Old French accident and classical Latin accidentem/accidere, which can mean accident, to happen, or to fall out or fall upon. The a- comes from ad-, which means to, and the suffix comes from cadere, which means fall. And is, weirdly enough, the origin word for case which used to mean “what befalls one”. So it went from “to fall to” to something happening to happening by chance to accident. With that fall in there, it kind of makes sense.
Incident showed up in the early fifteenth century meaning “something which occurs casually in connection with something else”. Which sounds a lot more like accident than accident does. Anyway, it comes from the Middle French incident and classical Latin incidentem/incidere, incident or fall. The in- means on in this case (don’t ask; prefixes are weirder than actual words) and added to cadere, it’s to fall on, which somehow morphed into what we know it as. Coincidence and coincide are both related, although they didn’t show up until the early seventeenth century. Those two words come from the Medieval Latin (so later than classical Latin) coincidere, which is incidere + co-, which is together. This makes the word “to fall on together”, which actually sounds a lot like what a coincidence is.
And there’s one more word we’re going to look at. Occident showed up in the late fourteenth century, meaning western, coming from the Old French occident and classical Latin occidentem, west. Occidentem comes from occidere, which can mean “fall down” or even “kill”. The fall down part at least makes sense, since the sun sets (or “falls down”) in the west. And amusingly enough, that word is also the origin for occasion, although via the Latin occasionem—opportunity. The o- comes from ob-, which means down or away. Not sure how falling away means opportunity, but there you are.
TL;DR: -cident means fall. Everything else is really confusing.