Need to understand my home electrical meter to see why bill is so high and/or if neighbor is on same meter
They're kilowatt-hours. If you use 1000 watts for 1 hour, it'll add one to the current number displayed. 

It's like an odometer on your car. It only counts up, and will never be at 0 except when it was brand new. 

Where is your neighbor's meter? If you can't find a second one, chances are you're paying for their power too. 

If your neighbor has their own meter, they will have their own circuit breaker panel too. If they're separate, then just turn off your breakers randomly and see if it affects your neighbor. If he complains that his heat or fridge keeps turning off then you know it's on your electrical service. 

Best time to turn them off would be when they're home and trying to cook. That way they'll notice if their oven or fridge loses power. 

If there is only one meter, then don't turn any breakers off. You're definitely paying for both homes if there is only one meter.