(1) A condition or property of a solution in which it has greater amount of solutes than that of another solution with which it is compared.
(2) A condition or property of a solution which has higher tonicity as the other solution with which it is compared.
(3) A condition in which there is a greater degree of tone or tension.
Hypertonicity occurs when the extracellular fluid has higher amounts of solutes than in the cytoplasm. In this condition, the water molecules diffuse out of the cell.
Related forms: hypertonic (adjective)
Compare: isotonicity, hypotonicity
See also: tonicity