Phenomenon of learning a new word that you've never seen before, and then seeing it being used (currently merged with the above)
A single word for a psychological bias (currently marked as duplicate of the first question above)
However, to me it seems that the first question is more about "coincidences," while the second is about a psychological phenomenon. The issue I have is that the second, merged question is pretty much the same as a new question that was recently asked:
But the top answer for the first question about "word meaning coincidence of reference to the unusual" is "synchronicity," which I don't think is the best answer for the putative duplicates.
Another probable duplicate, which again has top answers like "synchronicity" and "coincidence":
I think we should divide these questions into two groups of duplicates: one that asks for the name of this taken as an actual phenomenon (with the answers of "coincidence" and "synchronicity") and one that asks for the name of this taken as a perceived, illusory phenomenon.
Or something like this. It is sort of hard to determine exactly how to split them. The current situation is kind of confusing though; there's a lot of linked questions, a few are merged, and there's considerable duplication of answers across questions (sorry, I just contributed to that).
Other possible duplicates: