English
humidistat
From humid + -stat.
A compound of humid + -stat
Proto-Indo-European *wegʷ- ‘wet, moist’
…
Latin ūmeō ‘to be moist, wet or damp’
Latin ūmidus ‘moist, humid, damp, dank, wet’
Latin hūmidus ‘moist’
Old French humide
English humid
Today it means
noun A device that measures, or controls, the relative humidity of a gas.
Language periods are conventional ranges, not dates for this word.
Etymograph / humidistat