An electric appliance used for heating water and maintaining it at a constant temperature, otherwise known as a thermo pot or electric pot. A portable appliance of similar design is the airpot, but it doesn't heat the liquid contained, only maintain its temperature.
For appliances that can boil water that have a power base, see electric kettle. For appliances which connect into the plumbing directly for hot water, see water heater. For vessels used for water heating, see boiler.