Noun

(en noun)

In mining, a rich mine or vein of silver or gold.

The point at which two mother lodes intersect

By extension, anything which is a mine of wealth or yields a large income or return.

* {{quote-magazine, date=2013-08-31, volume=408, issue=8851, magazine=(The Economist), author=Bagehot

, title= The parable of the Clyde , passage=For two decades the bonanza on Scotland’s west coast continued. An occupation that had been seasonal and modestly profitable became year-round and lucrative. Baskets of herring put televisions into fishermen’s cottages and cars outside their doors. But fish, like oil and gas, with which Scotland’s continental shelf is also well-endowed, are not in unlimited supply.}}

Noun

(en noun)

Something that has been blown down by the wind.

A fruit that has fallen from a tree naturally, as from wind

They couldn't reach the branches, so they ate the windfalls .

(figuratively) A sudden large benefit; especially, a sudden or unexpected large amount of money, as from lottery or sweepstakes winnings or an unexpected inheritance.

* 2004: , Character: Profiles in Presidential Courage

Businessmen rushed to get every last commodity aboard a departing ship, hoping for a windfall once the world realized these would be the very last sacks of flour available, thus driving up prices.