Easton's Dictionary
(Esther 2:16), a word probably of Persian origin, denoting the
cold time of the year; used by the later Jews as denoting the
tenth month of the year. Assyrian tebituv, “rain.”
International Standard Bible Encyclopedia
te-beth', te'-beth (tebheth): The tenth month of the Jewish year, corresponding to January (Es 2:16).
See CALENDAR.