MOULIN

moulin, glacier mill

(noun) a chute through which supraglacial water enters a glacier, boring either to the bedrock or to the depth of common crevasse formation; “the icy river plunged, roaring, into the moulin’s blue depths”

Source: WordNet® 3.1

Etymology

Noun

moulin (plural moulins)

(geology) A cylindrical, vertical shaft that extends through a glacier and is carved by meltwater from the glacier’s surface.

Source: Wiktionary