This refers to when two or more people encounter each other in completely coincidental fashion. You might notice your old classmate from three countries away is now your waiter in a place you had no reason to expect them in, and you might say “wow, what a small world”. You might notice two people who you know from completely different spheres miraculously know each other. You might recognize by chance that your penpal has made a cameo at a venue you’re at.
But what was your most profoundly coincidental encounter?
Was transiting through the Iceland airport once and had a random thought about how I was quite far from anyone I know there. No sooner do I finish the thought I look about 20m in front of me and an old university classmate of mine is walking towards me.