A fall of water; a waterfall or cascade.
From Old French 'fall' (a fall) with the suffix '-age' indicating a condition or collection. This archaic term blends Germanic and Romance roots to describe the phenomenon of falling water.
Medieval mills depended entirely on measuring 'fallage'—the amount of water falling from a height—because more falling water meant more power to grind grain, so millers became expert hydrologists centuries before the science had a name.
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