Ossian is an Anglicised form of the Irish Oisín and the Scottish Gaelic Oisein.
The latter names are derived from a byname constructed from the element os ("stag").
[2] Ossian was one of several names popularised by the romantic works of James Macpherson (died 1796), composer of so-called Ossianic poetry.
[3] In consequence, it and other Ossianic names—such as Malvina, Minona, Orla, Oscar, and Selma—were enthusiastically adopted in Scandinavia in the nineteenth century.
The specific adoption of Ossian in Denmark does not appear to have been a direct result of the works of Macpherson, however, but owes its popularity there as an import from Sweden.