Windfall

I took this photograph on a visit to Tatton Park in Cheshire

The thought struck me that we use the word 'windfall' incorrectly. After all, there's nothing more certain and predictable that a gust of wind or strong downpour will cause an apple to fall from a tree; it's not the unexpected or even rare occurrence that people describe when an unexpected gift or other unplanned bounty appears in their lives.