Keseph is the standard Hebrew word for silver, appearing about 403 times in the Old Testament. Since coined money was not common in ancient Israel until later periods, keseph (silver by weight) served as currency. The word can mean both the metal itself and money in general. Its root may mean "to be pale" or "to long for" (desire for silver).
Silver in Scripture occupies complex theological terrain. It is a measure of value (30 pieces of silver was the price of a slave, Exodus 21:32), a material for sacred vessels in the Tabernacle, and a metaphor for refined speech (Proverbs 10:20 — "the tongue of the righteous is choice silver"). The love of silver (keseph) is condemned as a root of greed (Ecclesiastes 5:10). Most significantly, Zechariah 11:12–13 prophesies 30 pieces of silver as the "price" for the good shepherd — fulfilled in Judas' betrayal of Jesus (Matthew 26:15).