This word is hardly new, since it was used by J R R Tolkien at the beginning of the first volume of the Lord of the Rings, published in 1954. As with so many unfamiliar words in his works, he derived it from Old English, in this case the one usually written maðm, “a precious thing, treasure, valuable gift”, that was current in about the year 1000. Following Tolkien, it has gained significant currency online and in a few printed sources. To define the modern meaning, I can do no better than quote Professor Tolkien’s own words: “Anything that Hobbits had no immediate use for, but were unwilling to throw away, they called a mathom. Their dwellings were apt to become rather crowded with mathoms, and many of the presents that passed from hand to hand were of that sort”. It’s a useful little word for which there seems no simple alternative and now that we have come across it, mathom will no doubt become part of our family’s standard vocabulary, since we have an attic full of the stuff.