Drain pineapple; reserve syrup. Combine syrup, brown sugar, 3 tablespoonsteriyaki sauce, vinegar and catsup; set aside. Mix beef with remaining 2tablespoons teriyaki sauce and onion; shape into 20 meatballs. Brownmeatballs in large skillet; drain off excess fat. Pour syrup mixture overmeatballs; simmer 10 minutes, stirring occasionally. Dissolve cornstarch inwater; stir into skillet with pineapple. Cook and stir until sauce thickensand pineapple is heated through.