“ETF” stands for “Exchange Traded Fund”, which is exactly how it sounds; they are like mutual funds in many ways, but they trade on a normal stock exchange like a stock, with their value being determined both by the value of the underlying assets and the value of the ETF itself.
The typical hedge fund is designed to be a partnership arrangement with the fund manager acting as the general partner responsible for making investment decisions, and is one of the investment tools serious investors aspire towards.