According to ESPN, it does not stand for anything. Starting in 1979, ESPN was an acronym for Entertainment and Sports Programming Network. Then in 1985, ESPN dropped the long drawn out name no one could remember and went with ESPN.
This reminds me of an old singer named Prince Rogers Nelson, who then changed to Prince, then a silly symbol and then back to Prince. Long story short, you can become great by going from a long name to a short name, just don’t change to a symbol.
ESPN stands for ESPN