Emily Dickinson Lexicon

BOURN, n. [rather BORNE. Fr. borne, a limit; borner, to bound. In the sense of a stream, Sax. burn; Sw. brunn; D. bron; G. brunnen; Dan. brönd.]

1. A bound; a limit. That undiscovered country, from whose bourn No traveler returns. – Shak.
2. A brook; a torrent; a rivulet. [In this sense obsolete; but retained in many names of towns, seated on the banks of streams. In Scotland, it is still used in the sense of a brook, but they write it burn.]