convolution question[hlp]

Hello Everyone;
What's the real meaning of convolution of two signals in physical world? Does it mean adding of them?

I think that it is a way to compare two signals. It is defined by "*" sing. You have to multiply the first signal "a(t)" with the second "b(t) but being delayed and reversed and then integrate them....you can find several infos on the web or mathematical books for its definition and properties