XU \soo\ n. an old unit of Vietnamese currency, pl. XU

Usually when I introduce a currency, I work from the ‘dollar’ equivalent down to its smaller units. This time I’m going in the other direction, because every Scrabble player should have the xu deeply engraved in their brains…

Ten XU make up one HAO…

and ten HAO make up one DONG…

Inflation has taken its toll on Vietnam to such an extent that neither the xu nor the hao have been in use for years. However, all three terms (xu, hao, and dong) are sometimes used by Vietnamese Americans as colloquialisms for the local currency (cent, dime, and dollar).

Where did the unusual name xu come from? From the similar-sounding name of an old French coin called the SOU, which is nowadays used as slang for ‘a small amount of money’, as in ‘I don’t have a sou’. Sou in turn can be traced back to a gold coin used during the Roman Empire called the SOLIDUS.

In the Official Scrabble Players Dictionary, SAU is also listed as a variant spelling of today’s word, but I’ve been unable to find much evidence of that spelling anywhere.