Whats theDifference between Earth and Ground and Digital Ground and Audio Ground

Hi Mentor,
How are You?

I am a new Bee.
If I see a circuit it is filled with various Ground like Earth and Ground and Digital Ground and Audio Ground. What is the difference in all those Grounds. Does all give 0V or there is somthing else which I don't know.

Thanks in Advance
Sincerely
DigitalWork

Earth and ground, really mean the planet earth. Its a safety feature. So as you are standing on planet earth, you would hope that all the metal work you can touch will not send a current through you back to earth - this can be lethal!. So its connected directly to earth by some special path. I say special, because this path should be able to carry as much current as the supply can produce, else the path will burn out leaving the panel "live".
Digital circuits, when they switch cause spikes of current and voltages in their supply lines, so in a well designed circuit, they will flow directly back to the "digital " power supply, so as not to interfere with other circuits. So there could be a digital ground.
Audio signals are very sensitive to interference, so to have knowledge of where the audio signals are going, some times there is a special audio or signal ground. This is to keep power supply hum and digital signals away from audio circuits.
Old fashioned TV studios used to use a 4 pin mains connector, Live, Neutral, Mains Earth, Signal earth.
Frank