I see these three, especially pallet and palette, mixed up all the time – of course double letters, e at the end of a word and e or a are all classic ways to confuse spellings, so it’s hardly surprising that people get into a pickle with these.
Your palate is the roof of your mouth, and, by extension, can also be used to describe someone’s ability to appreciate different flavours and distinguish between them (wine tasters, for example, should have a good palate).
A palette is that board, usually round with a thumb hole in, that artists use to mix their paints, or the range of colours that an artist uses.
And a pallet is a portable flat platform used to store and stack other things – it’s often made of wood but you also find them in plastic. It’s also a kind of flat knife used to shape clay or plaster. And (whisper) it can be used to describe an artist’s palette, but let’s not confuse matters by doing that, OK?
“The artist cleared his throat, stepped up onto the pile of pallets that had stored his bread, grasped his palette and mixed some colours, and let the taste of the wine swill around his palate.”
You can find more troublesome pairs here and the index to them all so far is here.