Smith's Bible Dictionary (1863)
(gift of God), a eunuch (chamberlain, Authorized Version) in the court of Ahasuerus, one of those “who kept the door,” and conspired with Teresh against the king’s life.
Hastings' Dictionary of the Bible (1898)
BIG'THAN, OR BIG'THANA (gift of God), a chamberlain or eunuch who, with Teresh, a fellow-eunuch, sought to lay hand on King Ahasuerus. Esth 2:21; Esth 6:2.