A pile is a heap of things stacked on top of each other, often in a messy or casual way.
From Latin 'pilus' meaning 'hair' and later 'small ball', via Middle French 'pille' meaning 'heap'. The idea is of many small pieces gathered into one lump.
When we say we have a 'pile of homework', we’re borrowing a physical image to describe mental pressure. Your brain loves these concrete images, which is why 'pile up' feels more urgent than just 'increase'.
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