And now the conclusion. Of words that end in -cence but aren’t related to essence. I have to be specific because there are a ton of those and none of them are mentioned here.
Convalescence is one of those words that the N was just kind of thrown in there at some point, which seems to be a recurring theme for these words. It’s from the Middle French convalescence and Late Latin convalescentia, regaining of health. It comes from the classical Latin convalescere, recover, the origin word for convalesce, which we don’t really use that much these days. It’s a mix of the prefix com-, although that’s just an intensifier here, and valescere, grow strong. That word is actually related to valere, to be strong/healthy, which just happens to be the origin word for valiant.
Reminiscence first showed up in the late sixteenth century from the Middle French reminiscence and Late Latin reminiscentia, remembrance or recollection. That in turn is from the classical Latin reminiscentem, recollecting and reminisci, also recollecting. The word is a mix of re-, again, and menisci, which is from mens, or mind. So it’s to mind again. Or…remind. Man, you don’t often get one that makes total sense no matter how you look at it.
Reticence showed up in the early seventeenth century from the Middle French reticence and classical Latin reticentia, reservation or silence. The verb form is reticere, keep silent, a mix of re- (I think it’s just intensive here) and tacere, be silent. Which, you know, is where tacit comes from.
Magnificence showed up in the mid fourteenth century from the Old French magnificence, splendor, nobility, or grandeur, and before that, it was the classical Latin magnificentia, which meant splendor or beautiful (something nice, is what I’m getting at). Magnificentia comes from magnificus, majestic, a word that’s a mix of magnus, great, and facere, do or make. Magnificence is something that was made great.
TL;DR: Still none of these words are related. And every other -cence word is related to essence.