A.B.D
Arabic Bible Dictionary
GERAH
GERAH a bean, probably of the carob tree, the smallest weight, and also
the smallest piece of money, among the Hebrews, equal to the twentieth
part of a shekel (Exodus 30=>13; Leviticus 27=>25; Numbers 3=>47). This word
came into use in the same way as our word “grain,” from a grain of wheat.