ChristianAnswers.Net WebBible Encyclopedia
a Hebrew word, meaning a grain or kernel, and hence a small weight; the smallest weight
It was a bean, probably of the carob tree.
This was the the smallest weight and also the smallest piece of money among the Hebrews, equal to the twentieth part of a shekel (Ex. 30:13; Lev. 27:25; Num. 3:47). It was the twentieth part of a shekel, and equal to 12 grains.