If I have a diode like this:

Vi ------[>|------- Vo

I know that when Vi is greater than .7 volts, then it becomes a short circuit. When Vi is less than .7 volts it becomes an open circuit.

Now where I am confused is this case:

Vi -----|<]---------Vo

I am confused on when it becomes a short circuit. I would imagine that since the polarity of the battery in the diode is reversed that anything less than -.7 volts would make it short circuit. Anything greater than -.7 volts is open circuit.

Or is it the other way around, where anything less than .7 volts makes it a short circuit and anything greater than .7 volts makes it open circuit?

If someone could answer this question, it would be greatly appreciated, thanks.