Megillah is a Hebrew word meaning "scroll"
It can refer to in the Hebrew Bible:
The Scroll of Esther (Megillat Esther), read on the Jewish
holiday of Purim.
Any of the Five Magillot (the first part of the Hebrew
Bible), a group of books in Ketuvim (the third part
of the Hebrew Bible).
A less common usage refers to a Hebrew scroll on parchment
containing other full books from Nevi'im or Ketuvim
(the second and third part of the Hebrew Bible).
And in Rabbinic literature:
Tractate Megillah in the Talmud.
Megillah Taanit, a tannaitic document listing Jewish days
In talmudic jargon, any