irradiate (v.) Look up irradiate at Dictionary.com
c. 1600, "to cast beams of light upon," from Latin irradiatus, past participle of irradiare "shine forth, beam upon, illumine," from assimilated form of in- "into, in" (from PIE root *en "in") + radiare "to shine" (see radiate (v.)). Meaning "expose to radiation other than light" (originally X-rays) is from 1901. Related: Irradiated; irradiating.