word-forming element meaning "above, over, beyond," from Latin super (adverb and preposition) "above, over, on the top (of), beyond, besides, in addition to," from *(s)uper-, variant form of PIE root *uper "over." In English words from Old French, it appears as sur-. The primary sense seems to have shifted over time from usually meaning "beyond" to usually meaning "very much," which can be contradictory. E.g. supersexual, which is attested from 1895 as "transcending sexuality," from 1968 as "very sexual."
1550s, formed in English from saturate, or else from Late Latin saturationem (nominative saturatio), noun of action from past participle stem of saturare "to fill full, sate, drench," from satur "sated, full," from PIE root *sa- "to satisfy." Saturation bombing is from 1942, first in reference to Allied air raid on Cologne, Germany.