a natural or artificial place where water is collected and stored for use, esp. water for supplying a community, irrigating land, furnishing power, etc.

a receptacle or chamber for holding a liquid or fluid.

Geology . See under pool 1 ( def. 6 ) .

Biology . a cavity or part that holds some fluid or secretion.

a place where anything is collected or accumulated in great amount.

a large or extra supply or stock; reserve

a reservoir of knowledge.

noun

nothingness , zilch

noun

backlog , basin , cistern , container , fund , holder , lake , nest egg * , pond , pool , receptacle , reserve , source , spring , stock , stockpile , storage , store , supply , tank , tarn , cache , inventory , nest egg , treasure , fountain , well