Learn how to say Irradiation correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word irradiation:
the act or process of irradiating or the state of being irradiated
the apparent enlargement of a brightly lit object when it is viewed against a dark background
a shaft of light; beam or ray
the therapeutic or diagnostic use of radiation, esp X-rays
exposure of a patient to such radiation
another name for radiation, irradiance