Other forms: quenched; quenching; quenches
Quench means to put out, put an end to, or satisfy. If you're stranded in the middle of the desert with nothing to drink, you're probably dreaming of a nice big glass of ice water to quench your thirst.
Quench originally meant “extinguish fires.” That meaning still works today, but we've expanded it to also apply to quenching the fiery thirst of a summer marathon runner or quenching the hot flames of passion. If you want to get deep about the word quench, consider what Voltaire said: “Superstition sets the whole world in flames; philosophy quenches them.”