Discharged battery = 10 volts.
Dead means totally discharged.
Never let it go to 0 volts.
You'll injure it.
sometimes a dead battery looses its ability to sinc your electrical system when the ground in the battery fails (they wont jump) where a discharged battery will
If it's only discharged it can be recharged again.
If it's dead, it can't
Most people use those terms interchangably.
