What does the phase diagram mean by "liquid" at NTP? (The liquid and vapor coexist even when the situation is not on the curve)
The phase equilibrium diagram is for a system consisting of just water.

The diagram pressure is the total system pressure.

It may be equal to the saturated vapor pressure, if no external pressure is imposed on the system.

Or, it can be ( much ) higher, if some external pressure higher than the saturated vapour pressure exists.  In such a case all vapor is at equilibrium transformed to liquid or solid phase. 

Really high pressures can be seen in the water phase diagram for very high pressures, displaying rare ice phases.