ˈsistə(r)n noun
( -s )
Etymology: Middle English, from Old French cisterne, from Latin cisterna, from cista box, chest — more at chest
1. : an artificial reservoir or tank for holding or storing water or other liquids ; specifically : an often underground tank for storing rainwater collected from a roof
2.
a. obsolete : laver
b. obsolete : a large vessel for use (as in cooling wine) at the dining table
3. : a natural reservoir : a hollow place containing water
4. : a fluid-containing sac or cavity in an organism