Its source is an Old English expression meaning "Spear of the gods."
This boy's name is used in German, Czech, Norwegian, Swedish and Danish.
The name is derived by some from the Gaelic phrase os cara (friend of the deer).
It was used by James Macpherson in his Ossianic poems. Napoleon, an admirer of those works, imposed it on his little French godson, who eventually ascended the throne of Sweden as Oscar I (or Oskar I). As a result, this British name is now regarded as typically Scandinavian.