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
'Strange is our situation here upon the earth. Each of us comes for a short visit, not knowing why, yet sometimes seeming to divine a purpose.'