Water thermometer
Wa´ter ther`mom´e`ter
| 1. | (Physics) A thermometer filled with water instead of mercury, for ascertaining the precise temperature at which water attains its maximum density. This is about 39° Fahr., or 4° Centigrade; and from that point down to 32° Fahr., or 0° Centigrade, or the freezing point, it expands. |