It’s spelled “just deserts.” Not “desserts.”
One “s.” Really.
So why did so many smart people who saw the cover to the right as part of the upcoming “Fix It! Grammar” textbooks think it was wrong?
Because we’re dealing with three different words, spelled similarly or even identically, and with the only difference in pronunciation being the emphasis. But all three come from different etymological directions and with different meanings.
Let’s take them one at a time:
By far the yummiest word on this list, dessert comes from the Middle French desservir, meaning to clear the table. The servir part is the root word for serve. So, dessert is the last meal you are served at a meal.
Desert /DEZ-zert/ or /dez-ZERT/
Put the emphasis on the first syllable, and it’s the arid and usually sandy land. If the emphasis is on the second syllable, we’re talking about the act of leaving a place where you would have been of help. Thus: The soldier deserted his desert post.
Both definitions come from the same root word: serere means to join together. To desert means you’re no longer together with a place or a group of people, and a desert is no longer joined to signs of visible life.
Finally, we arrive at the third meaning, which has fallen out of general use, except for its being preserved in the phrase “just deserts.” The meaning is not a meal, nor is it to leave one’s place. Instead, it means “the quality or fact of meriting reward or punishment.” The root is the Anglo-French deservir, the same as our modern English word deserve. So, for the same reason deserve has only one “s,” desert in the phrase “just deserts” also has one “s.”
“Desert” is not the only otherwise-obsolete word that is preserved for us in the 21st century. Check out these top 12 words that are still in use, only because of a turn of phrase.