a thermometer having a bulb that is kept moistened when humidity determinations are being made with a psychrometer.
Compare dry-bulb thermometer.
Origin of wet-bulb thermometer
First recorded in 1840–50
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a thermometer the bulb of which is covered by a moist muslin bag, used together with a dry-bulb thermometer to measure humidity
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012