A Zuz (Hebrew-זוז; plural zuzzim Hebrew-זוזים) was an ancient Jewish silver coin struck during the Bar Kochba revolt. They were overstruck on Roman Imperial denarii or Roman provincial drachmas of Vespasian, Titus, Domitian, Trajan and Hadrian. Four Zuz, denarii or drachmas make a Shekel, a Sela or a Tetradrachm.
It has been suggested that its name is probably a corruption of the Greek Zeus which was the deity portrayed on the reverse of every drachm and tetradrachm (four drachma) of the Seleucid period and due to the prohibition of pronouncing names of idols, it was called "zuz". This name was used from the Greek era of drachmas, through the Roman era of Denarius, and then as the quarter denomination of Bar Kochba coinage. Another suggestion is that in Hebrew, the word "zuz" means "move", or "to move", so it was called "zuzzim" to show that it was constantly moving around, usually referring to the fact that Jews must give charity, or referring to the nature of money that it moves from one to another, alternating who is wealthy.
In the Talmud, the Zuz and the dinar are used interchangingly. The difference being that the Zuz originally referred to the Greek Drachma which was a quarter of the Greek Tetradrachm weighing approximately 17 grams; while the Dinar referred to the later Roman Denarii which was a quarter of the Tyrian shekels and had the same weight as the Jerusalem Shekels and the Roman provincial Tetradrachms at approximately 14 grams.
The Zuz is mentioned in the Passover Haggadah in the Passover song Chad gadya, chad gadya (One little goat, one little goat); in which the lyric of dizabin abba bitrei zuzei (Which Father bought for two zuzim (half shekel) repeats at the end of every stanza.