The Collaborative International Dictionary
Hygroscopicity
Hygroscopicity \Hy`gro*sco*pic"i*ty\, n. (Bot.) The property possessed by vegetable tissues of absorbing or discharging moisture according to circumstances.
Wiktionary
hygroscopicity
n. 1 (context uncountable English) The state of being hygroscopic. 2 (context countable English) The degree to which a substance is hygroscopic.