hypertonic

A solution with more osmotic pressure or tonicity than plasma or interstitial fluid. This results in a net flow of water across semipermeable membranes. Thus bathing cells in culture within a hypertonic solution will cause water to diffuse out of the cells across the cell membrane, causing the cells to shrivel or shrink.

References

Dorland's Medical Dictionary, 23rd ed., WB Saunders, Philadelphia, 1990