chassis ground definition

If by "normal" ground, you mean "earth ground" or "safety ground", then no. It's called "chassis ground" because typically it's used as the common negative return from the supply. (stuff used to be built on metal chassis, nowadays it's a layer of copper on the PCB.)

Conceptually, it's like the difference between "ground" (the green or bare wire) and "neutral" (the white wire) in house wiring.

They usually are connected together at one point (but only one!), but that's not absolutely necessary, if it's totally isolated, double insulated, all that schtuff.

Just FYI, the symbol for "earth ground" is usually:

| | ----- --- -

The chassis ground symbol is sometimes called "common", just to avoid that confusion.

Hope This Helps! Rich