radiation
Radiation (noun) means the way something spreads outward from a point or surface, similar to rays of light fanning out. Example: “The radiation of light from the lamp lit up the whole garden.”
Fill the gap
Can you complete this real example?
The _____ of light from the lamp lit up the whole garden.
Etymology
Borrowed from Latin radiatio, radiationis. By surface analysis, it is formed from radiate plus -ion.