It is said to be the 'Triple point' . Triple point is the right combination of temperature and pressure at which the substance can coexist in thermodynamic equilibrium in the liquid, solid and gaseous state. The Triple point of pure water is (273.16K , 32.01°F) and partial vapour pressure of 611.2 Pascal .
Source : http://www.sciencealert.com/13-science-facts-never-learned-high-school-2017