Meaning

verb satisfy (thirst)

verb make less active or intense

verb cause to heat and crumble by treatment with water

originFrom Middle English slaken (“to render slack, to slake”), from Old English sleacian, from Old English slæc (“slack”). Unrelated to, but possibly influenced by, the Old Norse sløkkva (“to extinguish”), compare Swedish släcka in the phrase släcka sin törst (“quench one's thirst”), släcka elden (“put out the fire”), and släckt kalk (“slaked lime”).

Etymology from Wiktionary, CC BY-SA 3.0