noun
reservoir
REZ-ur-vwar/ˈrezərvwɑːr/
A place or container storing a supply of fluid.
The reservoir behind the dam stores water for later use.

Etymology
A reservoir is a place for “keeping back” or storing something. The word first described a place where things collect or are kept in store, then developed the specific sense of a basin holding water.
In context
water could be released from the c41 and c41 a canals once the reservoir was about a third full to maintain and improve water supply
More examples
- Fill the coffee maker's reservoir with fresh water.
- The car's washer fluid reservoir is nearly empty.
- Several reservoirs supply drinking water to the city.
Forms
reservoir · reservoirs