I learned about this word today too. It stands for 'Joy Of Missing Out".
You were thinking of buying a coin and later that coin dumps to oblivion. That's JOMO!
Many times, especially with ethereum at some point. What about the price dumping simply after you sold that coin?
We need to find a new term for that as well.
This I've experienced recently with Casper. I tried to participate in the presale and I wasn't able to get in. It was discussed to be good project and to what is being discussed it had good volume and the price peaked above $1 on listing for trade. I was completely upset as I wasn't able to get in the queue. Further the price kept dropping, and now it is around $0.07 which is the pre-sale price.