p = ρ0gh
As you go deeper, the pressure gets bigger. So, yes, that "h" actually means the height of the liquid ABOVE you. A little odd, but kinda what I'd expect from this equation.
Definition of Pressure
P = F/A
Pressure is measured in Pascals, or N/m². Otherwise, a pretty easy equation, no? Except why does the equation and the next have variants of the letter p?
Definition of Denisty
ρ = m/V
Just like chemistry, but now with cooler variables! Also, don't forget the units: kilograms, m³, and kg/m³.
Universal Gravitational Potential Energy