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heap something up
to make something into a pile. He heaped the mashed potatoes up on my plate, because he thought I wanted lots. Heap up the leaves in the corner of the yard.
1. To pile something up: I heaped up the dirty clothes in the corner of my room. The floodwaters heaped debris up onto the beach.
2. To accumulate: Garbage heaped up in the streets.