from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An instrument that measures radiant energy by correlating the radiation-induced change in electrical resistance of a blackened metal foil with the amount of radiation absorbed.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A sensitive device for detecting and measuring the energy of electromagnetic radiation
from the GNU version of the Collaborative International Dictionary of English
- n. An instrument for measuring minute quantities of radiant heat, especially in different parts of the spectrum; -- called also actinic balance, thermic balance.
from The Century Dictionary and Cyclopedia
- n. An instrument devised by Professor S. P. Langley of the United States for measuring very small amounts of radiant heat.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an instrument that measures heat radiation; extremely sensitive
Greek bolē, ray; see gwelə- in Indo-European roots + -meter.(American Heritage® Dictionary of the English Language, Fourth Edition)
bolo- + -meter (Wiktionary)