Silvia did a great job! You can read the detailed explanation again here:

ETF  An exchange traded fund (ETF) is usually managed passively. This means it tracks the performance of a pre-defined index, such as the SMI. Like shares, ETFs can be traded on the stock exchange. is an abbreviation for exchange traded funds. In other words, ETFs are funds that are traded on the stock exchange. ETFs directly track an index (such as the SMI) which means they are passively managed – in contrast to many traditional funds. Since ETFs can be traded on the stock exchange, as an investor you can constantly keep track of the price trends of your ETFs. The current price of traditional funds is usually published only once a day. ETFs have less expensive administrative and distribution costs than traditional funds. However, since ETFs are traded on the stock exchange, as an investor you have to pay stock exchange fees, stamp duties and brokerage fees  The brokerage fee is charged by your bank for processing the purchase and sale of securities. It depends on the size of the order and the stock exchange you are trading on..