PILES ON is a phrase that means to add something to an already large amount. The crossword solutions for this phrase are LADES (5 letters), ADDS (4 letters), and ADDSTO (6 letters). LADES means to load or heap up, ADDS means to increase or augment, and ADDSTO means to add to or increase further. Together, these words describe the action of PILES ON, which is to add to an already large amount.