meaning of reservoir
1. A place where anything is kept in store; especially, a place where water is collected and kept for use when wanted, as to supply a fountain, a canal, or a city by means of aqueducts, or to drive a mill wheel, or the like.
2. A small intercellular space, often containing resin, essential oil, or some other secreted matter.
3. tank used for collecting and storing a liquid as water or oil