cistern

noun6

1. •
   A reservoir or tank for holding water, especially for catching and holding rainwater for later use.

   • For cistern valves, they are well adapted—opening the full area upon the least descent of the ball, and are not liable to be set fast. — 1847
2. •
   In a flush toilet, the container in which the water used for flushing is held; a toilet tank.

   • It is possible to connect your tank to your toilet cistern and/or garden, so that even if the water is not drinkable it still can be used productively to make major water savings. — 2003
3. •
   The receptacle that holds the fuel in an oil lamp.
4. •
   The vessel surrounding the condenser in a steam engine.
5. •
   A cisterna.
6. •
   A shallow, typically oval, vessel made of porcelain, pottery, or glass.