Strong’s Dictionary of Hebrew Words:
Meaning:
probably of Persian origin; Sivan, the third Heb. month
Potts’ Bible Proper Names:
Month:―third month of Jewish sacred year, Esth. 8:9. {Mensis}
From Manners and Customs of the Bible:
Esther 8:9. In the third month, that is, the month Sivan.
Sivan corresponded nearly to our month of June.