moulin
moo-LAN
A vertical shaft or tube in a glacier through which meltwater pours from the surface to the base. Moulins form when surface streams find a crevasse and begin to bore downward, the falling water enlarging the hole through thermal and mechanical erosion. The sound of water falling into a moulin is audible from a distance — a deep, roaring pour.
Etymology
French for "mill" — named for the loud, roaring noise the falling water makes, like the mechanism of a watermill.
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