temperature at which a mixture of ice and air-saturated water at a pressure of one atmosphere is in equilibrium, represented by 273,15 K, 0 °C and 32 °F, temperatuur, mille juures atmosfääri rõhul jää ja õhuga küllastunud vee segu on tasakaalus, mida esindab temperatuur 273,15 K, 0 °C ja 32 °F