Compounding example

Don't pay attention to all of the numbers lol, this is just to provide context... can you please explain what is "compounding" in compounding example"?

A $10,000 lump sum one time investment at 1% would double to $20,471 in 72 years. If the return increases from 1% to 4%, what do you think happens?

Instead of 72 years, it now takes only 18 years for money to double. If we use a steady 4% rate of return in our compounding example, $10,000 over the same 72 years grows to $168,423.