Here's a four-letter word for you to mull over (though, actually, let's save mulling things over for tomorrow).
So what is a mull, anyway?
The most famous mull, because of Paul McCartney and Denny Laine etc, is probably the Mull of Kintyre.
The Mull of Kintyre is the promontory in the bottom middle of the picture. It's in Scotland, in case you don't recognise the map.
Now, there's no chance for people like me who live miles away from the sea for spotting the promontory sort of a mull, but luckily there are other mulls to spot.
One's a soft muslin cloth. It's the sort of thing used for cooking, perhaps, or (in this household) for covering a moth trap to ensure the tiniest moths don't escape from it before they can be identified.
Or, if you're doing infrared spectroscopy (and aren't we all?) then you may well prepare a solid sample for analysis by crushing it up with oil to form a thick substance called a mull.
But the easiest mull to spot is the layer of top soil that forms wherever there's vegetation, but the soil isn't waterlogged enough to turn the ground sour.
It makes you feel quite differently about soil once you know you can call it mull, doesn't it.
Spot the frippet: mull. The fabric used to be called mulmull, from the Hindi malmal; the topsoil comes from the Danish muld; and the promontory is related to the Gaelic maol.
I'm afraid none of the infrared spectroscopy people are saying from where their sort of mull came,