The New Israeli Shekel (NIS for short) became Israels official currency in 1985. The government created the NIS by knocking three zeroes off the old shekel prices of everything following runaway inflation.
The shekel replaced the lira, around 1980. The lira which derives from the Latin for pound, was a hangover from the British Mandate.
Shekel has deep roots in Hebrew. The verb lishkol means to weigh, an essential act in all business transactions. (It also means to consider or deliberate.)
Indeed, the first biblical reference to shekel is when Abraham buys the Cave of Machpelah from Ephron the Hittite. Ephron names the price of 400 shekels of silver, and Abraham duly weighs (vayishkol) out the coins.
Exodus 30:13 establishes the value of the shekel as 20 gerahs, or seeds of a carob fruit, which all have an identical weight and therefore were useful tools of measurement in the ancient Middle East. Gerah came to refer to a small coin and is related to the modern agora, one hundred of which make up one New Israeli Shekel.
Shekel is used in English as an antisemitic synonym for money, as in: Hes really raking in the shekels.