from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun An instrument that indicates changes in atmospheric humidity.
from The Century Dictionary.
- noun An instrument or apparatus in which the hygroscopic property of some substance is employed for indicating approximately the humidity of the air, without attempting its accurate measurement.
from the GNU version of the Collaborative International Dictionary of English.
- noun (Physics) An instrument which shows whether there is more or less moisture in the atmosphere, without indicating its amount.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun An
instrumentthat indicates changesin atmospheric humidity
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun hygrometer that shows variations in the relative humidity of the atmosphere
from Wiktionary, Creative Commons Attribution/Share-Alike License
hygro- + -scope
In this way a small area of the surface of the earth is converted into a hygroscope, and these test surfaces tell us whether the ground is cooled to the dew-point or not.