To quench means to satisfy a thirst by drinking something, or to put out a fire or flame. After running around outside on a hot day, a cold glass of water quenches your thirst completely. When firefighters spray water on flames, they quench the fire.

The word carries a sense of complete relief and satisfaction. A small sip might help reduce your thirst, but a long drink quenches it fully. Similarly, when you quench a candle flame by pinching it out or dousing it with water, the flame goes out entirely.

You might also hear quench used more broadly to describe satisfying other strong desires or needs. A curious student might quench their thirst for knowledge by reading everything they can find about ancient Egypt. In metalworking, craftspeople quench hot metal by plunging it into water or oil, which cools it rapidly and makes it harder. The word almost always suggests something intense being completely satisfied or extinguished, rather than partially reduced.