Shethar
SHETHAR (shē'thar, Heb. shēthar). One of the seven princes of Persia and Media who “saw the king’s face” in the days of Xerxes (Esth.1.14).
SHETHAR she’ thär (שֵׁתָר). One of the seven princes at the court of Ahasuerus who had the right of access to the presence of the king except when he was in the company of one of his wives (Esth 1:14). The name is prob. Pers.
International Standard Bible Encyclopedia (1915)
One of the "seven princes" at the court of Ahasuerus (Es 1:14); these princes "sat first in the kingdom" and had the right of entrance to the king’s presence at any time, except when he was in the company of one of his wives. (According to Marquart, Fund., 69, Shethar comes from sh-r-sh-th-y with which the Persian siyatis, "joy," is to be compared.) The word has never really been satisfactorily explained; it is presumably Persian.