Being sensitive to moisture, such as certain tissues.

1. Possessing a marked ability to accelerate the condensation of water vapor; applied to condensation nuclei composed of salts which yield aqueous solutions of a very low equilibrium vapor pressure compared with that of pure water at the same temperature.

2. Pertaining to a substance whose physical characteristics are appreciably altered by effects of water vapor.

3. Pertaining to water absorbed by dry soil minerals from the atmosphere; the amounts depend on the physicochemical character of the surfaces, and increase with rising relative humidity.