saturation (n.)

1550s, "act of supplying to fullness, complete satisfaction of an appetite" (Coverdale, a sense now obsolete), formed in English from saturate (q.v.), or else from Late Latin saturationem (nominative saturatio) "a filling, saturating," noun of action from past-participle stem of saturare "to fill full."

The sense in chemistry is by 1670s, "impregnation until no more can be received;" the general sense of "action of thoroughly soaking with fluid, condition of being soaked" is by 1846. By 1964 in reference to a type of color adjustment on a television screen; earlier it had been used in chromatics for "degree of intensity" (1878). Saturation bombing is from 1942 in reference to mass Allied air raids on Cologne and other German cities; the idea is credited to Arthur Harris.

"Saturation bombing," dropping as much as fifty-one tons a minute, depends on clockwork precision and a gigantic organization behind the lines. In the famous German raid on Coventry, 225 tons were dropped over a period of eight hours. In the British raid on Hamburg on July 27-28, 1943, more than 2,300 tons were dropped in forty-five minutes. A single raid of this type uses more than 100,000 air and ground personnel. [British Information Services, "The First Four Years," 1943]