ETF stands for Exchanged Traded Funds. They are known as trackers in France.
ETFs are real index funds which trade on a Stock Exchange and track the performance of an index such as the CAC40 or Euronext 100. Like shares, they are easy to buy and sell all day at real time market prices and with the same brokerage fees.
This is a companion discussion topic for the original entry at https://www.bestbrokers.co.uk/definition/etf.html