What do you call a single drop of sleet?

We apparently have different definitions, as others have noted. In my dialect, sleet is wet. It may include some hard bits of ice, but if it’s not wet, it’s not sleet.

Hence, there is no single bit of sleet. It’s always an amalgam.

This may be why American forecasters are using that term “wintry mixture” which is new to me. We already have a term for it:sleet. If Americans don’t have that term, I can see why they would need to invent one for it.

(Piper, whose home town is currently dealing with -40 temps.)