If you're babysitting a child who's afraid of monsters, you might want to check under her bed and in her closet to reassure her that they are monster-free. Her quelled fears will allow her to fall asleep quickly. The adjective quelled comes from quell, "put an end to" or "subdue." The Old English version of this word, cwellan, meant "to kill, murder, or execute." It took on a milder meaning in the fourteenth century.