BOTH'NIAN, adjective Pertaining to Bothnia, a province of Sweden, and to a gulf of the Baltic sea, which is so called from the province, which it penetrates. Pinkerton uses Bothnic, as a noun for the gulf, and Barlow uses bothnian in the same manner.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI