a device for measuring intensity of radiation, especially that of the sun.

Compare actinograph.

Origin of actinometer

First recorded in 1825–35; actino- + -meter
Related formsac·tin·o·met·ric [ak-tin-oh-me-trik, ak-tuh-noh-] /ækˌtɪn oʊˈmɛ trɪk, ˌæk tə noʊ-/, ac·tin·o·met·ri·cal, adjectiveac·ti·nom·e·try, noun Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Related Words for actinometer

actinometer, photometer, radiometer

Examples from the Web for actinometer

Historical Examples of actinometer

British Dictionary definitions for actinometer



an instrument for measuring the intensity of radiation, esp of the sun's rays
Derived Formsactinometric (ˌæktɪnəʊˈmɛtrɪk) or actinometrical, adjectiveactinometry, noun
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

actinometer in Science



Any of several instruments used to measure radiation, such as a pyrheliometer.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.