Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
A tax imposed by a king on his subjects (2 Sam. 20:24; 1 Ki. 4:6; Rom. 13:6). In Mt. 17:24-27 the word denotes the temple rate (the "didrachma," the "half-shekel," as rendered by the R.V.) which was required to be paid for the support of the temple by every Jew above twenty years of age (Ex. 30:12; 2 Ki. 12:4; 2 Chr. 24:6, 9). It was not a civil but a religious tax.
In Mt. 22:17, Mk. 12:14, Lk. 20:22, the word may be interpreted as denoting the capitation tax which the Romans imposed on the Jewish people. It may, however, be legitimately regarded as denoting any tax whatever imposed by a foreign power on the people of Israel. The "tribute money" shown to our Lord (Mt. 22:19) was the denarius, bearing Caesar's superscription. It was the tax paid by every Jew to the Romans.