From Hebrew הֲדַס (hadas) meaning “myrtle tree”. There’s only one person named Hadassah in the Bible. It’s the Hebrew name of Esther, who became the wife of king Ahasuerus and thus queen of Persia in place of Vashti.

The name Hadassah occurs only once in the Bible, in Esther 2:7, which reads: “…and he was bringing up Hadassah, that is Esther, his uncle’s daughter”.