An Etymological Dictionary of Astronomy and Astrophysics

Any instrument for measuring the intensity of radiation, especially that of the Sun, in its thermal, chemical, and luminous aspects.

Etymology (EN): Actinometer, from actino- combining form with the meaning “ray, beam,” from Gk. aktis, aktin
“ray,” + → -meter.

Etymology (PE): Partow, → ray; + -sanj, → -meter.