What is the etymology of the word denarius, the Roman coin?

The denarius (pl. denarii) was the standard Roman silver coin from its introduction in the Second Punic War c. 211 BCE to the reign of Gordian III (238–244 CE), when it was gradually replaced by the antoninianus.

The word denarius is derived from the Latin deni "containing ten", as its value was originally of 10 asses. [An "as" or "assarius" was a bronze or copper coin used during both the Roman Republic and Empire.] The word for "money" descends from it in Italian (denaro), Slovene (denar), Portuguese (dinheiro), and Spanish (dinero). Its name also survives in the dinar currency.