hygrometer

American  

[hahy-grom-i-ter] / haɪˈgrɒm ɪ tər /

noun

1. any instrument for measuring the water-vapor content of the atmosphere.

---

hygrometer British  

/ ˌhaɪɡrəˈmɛtrɪk, haɪˈɡrɒmɪtə /

noun

1. any of various instruments for measuring humidity

---

hygrometer Scientific  

/ hī-grŏm′ĭ-tər /

1. Any of several instruments that measure humidity. The most common type of hygrometer consists of two, side-by-side mercury or electronic thermometers, one of which has a dry bulb, and one of which has a bulb wrapped with a wet cotton or linen wick. As water evaporates from the wet bulb, it absorbs heat from the thermometer, driving down its temperature reading. The difference in temperature between the two thermometers is then used to calculate the relative humidity. This type of hygrometer is also called a psychrometer. Other hygrometers make use of the temperatures at which dew forms and disappears to calculate the relative humidity. Older hygrometers used the length of a strand of hair, which stretches when it absorbs moisture, to measure relative humidity.

---

Other Word Forms

• hygrometry
  noun
• hygrometric
  adjective
• hygrometrically
  adverb

Etymology

Origin of hygrometer

First recorded in 1660–70; hygro- + -meter

Example Sentences

If yours doesn’t, you can buy a basic hygrometer for $10 or less to monitor water vapor in the air around you and test the performance of a humidifier you already own.

From Seattle Times • Oct. 31, 2022

Another pro-tip: Keep the air at 40 to 60 percent humidity, which helps stop aerosol transmission, Dr. Pirzada said, by using a hygrometer or a humidifier to measure the level.

From New York Times • Apr. 17, 2022

Some humidifiers include a built-in hygrometer, an instrument that measures humidity in the air, so you can easily check room humidity.

From Washington Post • Sep. 6, 2021

By Cline’s day, a basic hygrometer measured the degree of moisture in the air by using two glass bulbs, each at one end of a glass tube.

From Time • Aug. 4, 2015

A simple hygrometer can be made by a piece of catgut and a straw.

From Harper's Young People, August 17, 1880 An Illustrated Weekly by Various