This article is from the Nordic countries FAQ, by Antti Lahelma and Johan Olofsson, with numerous contributions by others.
The Roman historian Pliny the Elder mentions in 67 CE an island called
"Scadinauia" in the sea at the edge of the world, north of Germania.
This, as it dawned much later to the civilized world, was in fact no
island but the southern tip of Sweden, the province of Scania (Skåne).
The name is thought to be related to the word "skada", or "damage"
that could be done to ships by the sand reefs outside southwestern
Sweden. The "-avia" ending, on the other hand, probably comes from a
word meaning "island", cf. contemporary Norwegian "øya". Thus the
original definition of the word "Scandinavia" was purely geographical:
it referred to the Scandinavian peninsula -- contemporary Sweden and
Norway.
Later, as people became more conscious of their culture, formed
political unions, colonized previously uninhabited areas and conquered
the land of their neighbours, the definition of the word started to
stretch. "Scandinavia" became more a political and cultural concept
than a geographic one. And since cultural boundaries tend to be less
clearly definable than geographic ones, and political boundaries on
the other hand move around quite a bit, the current use of the word is
a bit of a mess.
 
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