water-thermometer
Wa"ter ther*mom"e*ter. (Physics) Defn: A thermometer filled with water instead of mercury, for ascertaining the precise temperature at which water attains its maximum density. This is about 39º Fahr., or 4º Centigrade; and from that point down to 32º Fahr., or 0º Centigrade, or the freezing point, it expands.