Hi,
I keep reading about the possible ETF SEC approval, but could anyone explain to me what it means? It means exchange traded fund, but there already are bitcoin exchanges in the US right? I'm confused.
ETF does not trade only cryptocurrencies, therefore ETF is not a crypto exchange or FIAT-exchange, so don't confuse online exchanges with ETF. If bitcoin is officially accepted by ETF, if BTC receives regulatory approval from USD ETF, the things for all the bitcoin owners will become interesting

. Hope this fuzz brings us toward USD ETF's approval!
You can read some more on Wikipedia for start.
https://en.wikipedia.org/wiki/Exchange-traded_fund