diradiation

English

Etymology

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium. Particularly: “di- + radiation? But what's the link with the number two?”)

Noun

diradiation (uncountable)

1. (obsolete) The emission and diffusion of rays of light.
   • 1725, John Harris, Lexicon Technicum: Or, An Universal English Dictionary Of Arts And Sciences:

     ACTINOBOLISM, is the same with the Diffusion or Diradiation of Light or Sound, by which it's carried or flows every way from its Centre.

   • 1829, London Encyclopaedia; Or, Universal Dictionary of Science:

     ACTINOBOLISM, from ακτιν, a sum beam, and βαλις, a plumb line, in physics, diffusion, or the diradiation of light or sound by which it flows every way from its centre.

Part or all of this entry has been imported from the 1913 edition of Webster’s Dictionary, which is now free of copyright and hence in the public domain. The imported definitions may be significantly out of date, and any more recent senses may be completely missing.
(See the entry for “diradiation”, in Webster’s Revised Unabridged Dictionary, Springfield, Mass.: G. & C. Merriam, 1913, →OCLC.)