The triple point of any substance is that temperature and pressure at which the material can coexist in all
three phases (solid, liquid and gas) in equilibrium.
Specifically the triple point of water is 273.16 K at 611.2 Pa
Answered by: Ryan Hitch, MPhys Physics, University of Hull
'Arrows of hate have been shot at me too, but they have never hit me, because somehow they belonged to another world with which I have no connection whatsoever.'