The first name Magnus is of Norse, Danish, Latin, Scottish, Swedish origin. It is often a boy name. It has the following meaning(s):
Norse: Fighter
Danish: Great
Latin: Great/Greatest. A Name Popular in Scandinavia During the Viking Period. A Number of Norse Kings Bore This Name
Scottish: Great; a Borrowing from the Latin, Magnus is Derived from Magnus (Great). The Name Was Brought to the British Isles by the Scandinavians During the Middle Ages. Manus is the Gaelic Form. (Mag-nus)