Psithurism

 The BBC's Winterwatch series has been a welcome window on the natural world in these hunkered-down times ('It's what you pay your licence fee for,' as presenter Chris Packham likes to say, exultingly, after a particularly choice item – and it is indeed one of the few BBC programmes I would actually miss).
Watching it last night I actually learned a new word – 'psithurism' (the 'p' is silent). It describes the sound made by the wind among the leaves in the tree canopy of a woodland. It derives from the Greek psithuros, a whispering, and it sounds much like what it denotes. Not as versatile as the broadly similar 'susurration', but a useful word to have about you on a woodland walk: 'Harken to that psithurism!'