there is nothing called officially in my opinion.
you can call a coin dead for many reasons for example:
- when the developer gives up on his own project and nobody else is interested in picking up where he left off.
- when the price goes to 1 satoshi and there is no buy orders and nobody is buying from the asks either.
- you can even go as far as calling a coin dead when it is getting dumped real hard down to 1 satoshi
- technically a coin is dead if there is no one mining it and there is no full node of it available any more.
Nice explained, in this case I have many dead coins on my yobit wallet. Before I collected them just for fun and I thought that one day maybe they worth a bit more. Now I have a lot of coins that worth 1 satoshi.
Thanks for nice explanation once again.