Windfall

Windfall.  That's what was waiting for me when I went out to the backyard the other day and three of the neighbour's lemons had fallen off their tree and on to our lawn.  I'd just thought "free lemons" while I scooped them up and took then inside. But they were a "windfall" - because the wind had made them fall off the neighbour's tree and on to the ground on our side of the fence ... which, as well as picking them, had also made them (legally?) ours.  I'm not sure when the term went from windfall (an apple or other fruit blown down from a tree or bush by the wind) to windfall (a large amount of money that is won or received unexpectedly) but you can see how they are essentially the same - a reward for.little or no effort.