Where did the word gothic originate?

The Word gothic is derived from a European tribe called the Goths, thought to have originated in southern Sweden, who spread all over Europe.

The Word is now used to describe an architectural style and, as a derivation of that, a genre of literature based on dark deeds in crumbling "gothic" mansions and castles. The modern trend in style called "goth" is similarly based on dark or arcane themes.