Tamar f. Hebrew תָּמָר 'date palm'.
The name of an Old Testament character, a 12th-13th C Georgian queen, a 13th C queen consort of Rum, and a 16th C Georgian princess. Wycliffite Bible (1395): Tamar, Thamar.
The name came into use among Protestants in the second half of the 16th C. In Georgia, the name was quite popular due to it also being the name of a mythological sky goddess, though the goddess name is almost certainly of a different (and uncertain) etymology.