Boyd’s Bible Dictionary:
(Indus). The indefinite country which bounded the Persian empire on the east (Esther 1:1; 8:9).
Concise Bible Dictionary:
This was the boundary of the Persian empire of Ahasuerus on the east, as Ethiopia was its boundary on the west (Esther 1:1; Esther 8:9). India is not mentioned elsewhere in scripture, but Solomon’s ships may have visited it in their three-year voyages for sandal wood, apes, peacocks, and such (1 Kings 10:22).
Strong’s Dictionary of Hebrew Words:
Meaning:
of foreign origin; Hodu (i.e. Hindu-stan)
Jackson’s Dictionary of Scripture Proper Names:
flee ye away: give ye thanks
Potts’ Bible Proper Names:
He murmured in a whisper; praise:―country E. of Persia, Esth. 1:1. {Susurro murmuravit}