The Collaborative International Dictionary
Wet-bulb thermometer
Wet-bulb thermometer \Wet-bulb thermometer\ (Physics) That one of the two similar thermometers of a psychrometer the bulb of which is moistened; also, the entire instrument.
WordNet
wet-bulb thermometer
n. a thermometer with a bulb that is covered with moist muslin; used in a psychrometer to measure humidity [ant: dry-bulb thermometer]