Now I like to keep up on my Latin and so I was translating some Pliny a few days ago and ran into the phrase (Epistulae 6.3) " centum milium nummum" literally, a hundred thousand nummi, which in this letter is the selling price of a piece of land. Since Pliny lived in the First Century AD I found his use of the term Nummus, a rather odd choice of words. Why not sesterces or denarii? Why not the use of a term with no ambiguity, something not a good idea when making a large purchase? Looking this up in an English translation of Pliny I found it translated as sesterces, one hundred thousand sesterces. It seems that Pliny and his correspondent knew full well that the word nummus in this context meanstsestertius. This got me to thinking that my own understanding of what a nummus was might be incorrect. I decided to research this term a bit. It looks like the Romans picked up the term from (where else) the Greeks. In Southern Italy and Sicily the Greeks were calling their silver staters by the term NOMOS. Why that word for a coin? The word NOMOS appears in my Classical Attic Greek dictionary as law or custom, but not as a word for coin, any kind of coin. But it is a commonly used word in Magna Graecia, perhaps in the sense that their staters were lawfully minted and the customary coin of commerce. For whatever reason the Romans picked it up and used it for their coinage. But what exact, individual denomination coin? Looking up nummus (also sometimes spelled with only one m) in Latin sources is not much help. It seems that the word could be used for several common Roman coins. I kept running into definitions that were maddingly broad and nebulous. To the Greeks it was a two drachma coin, to Romans a sestertius or a slang term for a denarius or just money in general as in our term cash. Then, to top it off, some Roman authors of the early Empire like Horace and Martial use the Greek variation nomisma, a term I always thought to be a much later Byzantine term but one apparently already in use centuries earlier (and still in use as a word for coin in modern Demotic Greek). Trying to nail down a definition of what is a nummus (or nomisma) by using dictionaries was not working, so, I tried books on numismatics. Stevenson's old dictionary of Roman coinage has the numus as "a coined piece of metal". Harl explains a nummus as a tiny billon or bronze and suggests a weight of .6 to 2.5 grams, but he also calls the follis of Diocletian a nummus and that is usually a larger and heavier coin. The Greek variation of nummus, the nomisma in Rynearson and Sear is mentioned as a coin that could be in either gold, electrum, silver or bronze. Carson's World of Coins says that nomisma was the common word for the solidus. i am getting the impression that nummus can be used for any coin depending on context, which is not so good if one does not know the context. If any readers can offer some insight on how these words, nummus and nomisma can be used with any kind of precision, please chime in on this and tell us how they ought to be used. Anyway, I have posted a few coins below which I think were called by the terms NOMOS, nummus or nomisma in their day. If readers can add to this list or the discussion please do and remember that if a person says or writes that someone spent a nummus or nomisma on something it does not mean a whole lot without more context. First is a nomos of the Southern Italian city-state of Velia with Athena on the obverse. It is a di-drachma of 7.4 grams and was minted about 300 BC. It is Sear 269. Next is a sestertius of Titus issued about the time Pliny was killed by the eruption of Vesuvius in 79 AD. it weighs a hefty 24 grams, not what I think a nummus should weigh. it is Sear 2527. The third coin is a follis of Diocletian from about 300 AD weighing in at 8.4 grams, again somewhat heavy for what I have though a nummus would be. Next are two smaller bronzes, a bronze Ae 3 nummus of Jovian, Sear 4086, issued right after he succeeded Julian and a very small Ae 4 nummus of Honorius. Next, a 40 nummia follis of Justin II, ca. 570 AD showing us what the Byzantines though a nummus (nomisma) ought to look like if this coin is worth forty of them. it is Sear 360. The last is an electrum nomisma of Michael VII issued about 1075 AD , weighing 4.4 grams and is Sear 1868. Again, any other examples of what might have been labelled a nomos, nummus or nomisma in its day or any thought on this, please join in.