Etf is an index fund, but index funds are not just ETFs. Etf is an index fund on the market, and there are also index funds off the market. When investors invest in index funds, they can choose on-site or off-site according to their needs.

Index fund is a fund that invests in an index way, and its goal is to obtain a return on investment roughly equivalent to the market average.

Exchange-traded funds (ETFs), also known as transactional open-end index funds, index stock funds and exchange-traded funds, are open-end funds listed and traded on exchanges, with variable fund shares.