means A heap of things—papers, laundry, regrets—stacked loosely on top of one another, usually growing faster than it shrinks.

from From the Latin 'pila,' meaning a pillar or stone bulwark, which also gave us the 'pile' driven into the ground to hold up bridges and buildings. The sense drifted from a single sturdy column to any mass heaped up high—so the laundry mountain on your chair shares an ancestor with load-bearing architecture, which the essence already suspected.