from The Century Dictionary.
- noun The measurement of the intensity of radiation.
from the GNU version of the Collaborative International Dictionary of English.
- noun The measurement of the force of solar radiation.
- noun The measurement of the chemical or actinic energy of light.
from Wiktionary, Creative Commons Attribution/Share-Alike License.
- noun the measurement of the
heating powerof electromagnetic radiation, especially that of solar radiation
- noun the measurement of the chemical or actinic energy of
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- noun measuring the intensity of electromagnetic radiation (especially of the sun's rays)
from Wiktionary, Creative Commons Attribution/Share-Alike License
These is also a photometric photographic catalogue of the stars nearest to the pole in PARKHURST's “Yerkes actinometry” (1912),  which contains all stars in B.
n. - instrument measuring heating power of the sun's rays; Photography, instrument for calculating exposure times. actinometry, adj.