WordWeight : Weighing the Words

Pronunciation : Ir*ra`di*a"tion
Part of Speech : n.
Etymology : [Cf. F. irradiation.]
Definition : 1. Act of irradiating, or state of being irradiated.

2. Illumination; irradiance; brilliancy. Sir W. Scott.

3. Fig.: Mental light or illumination. Sir M. Hale.

4. (Opt.)

Defn: The apparent enlargement of a bright object seen upon a dark ground, due to the fact that the portions of the retina around the image are stimulated by the intense light; as when a dark spot on a white ground appears smaller, or a white spot on a dark ground larger, than it really is, esp. when a little out of focus.
Source : Webster's Unabridged Dictionary, 1913