gruel (n.)

late 12c., "meal or flour made of beans, lentils, etc.," from Old French gruel "fine meal" (Modern French gruau), a diminutive form from Frankish *grut or another Germanic source, cognate with Middle Dutch grute "coarse meal, malt;" Middle High German gruz "grain," from PIE *ghreu- "to rub, grind" (see grit (n.)). Meaning "thin porridge or soup" is late 14c.