The Hebrew word Adar (H144) refers to the twelfth month of the sacred Hebrew calendar, roughly corresponding to February-March in the modern calendar. It is mentioned in Esther 3:7, 3:13, 8:12, and 9:1, 15, 17, 19, 21 in connection with the decree against the Jews and their deliverance.
The name is borrowed from the Babylonian/Akkadian Addaru and was adopted during the exile period. It replaced the older Canaanite month names used in pre-exilic Israel.
Adar is theologically significant as the month of Purim, the festival celebrating the deliverance of the Jewish people from Haman's genocidal plot recorded in the book of Esther. On the 14th and 15th of Adar, Israel commemorates this miraculous rescue.
The providence woven through the book of Esther — where God's name never appears but His hand is everywhere — culminates in Adar. The month Haman chose by lot (pur) to destroy Israel became the month of their salvation. "The very day the enemies of the Jews had hoped to overpower them was reversed" (Esther 9:1) — a pattern that finds its ultimate expression in the cross, where the day of death became the day of victory.