The word 'Goth' does indeed refer to a tribe of the indo-european kind. 
The Goths slowly integrated into the melting pot of Europe and basically 
disappeared. 

The word 'gothic' is first found in common usage in 1611, referring 
mainly to an 'uncivilized lack of taste or education'. The people who 
built in the 'gothic' style would have never used this term. These
people were monks or artisans who worked for the church to build a land 
of Cathedrals from the 11th century on. They also built castles and other 
edifices. The 16th century saw a large amount of turmoil with the reform 
and all. This opened up the architecture field quite a bit. This new wave of
artists looked back on what they saw as a bland repetitive style of 
architecture as 'gothic'. Unfortunatly, because of the shallowness of the 
learned men at that time, it stuck. It was also referred to as Ogive - or 
the characteristic arch of this style - this word is usually used by most
politically correct historians. 

The fact is: Ogive architecture today is extremely inspiring and beautiful. 
The nameless men who designed and built these works of grandor were very 
talented and inspired. One merely has to look at the Cathedral of 
Chartres, Paris, Amiens, Canterbury or any of the other edifices of this 
age to realize irony of using 'gothic'. In fact, to augment the irony, the 
popular opinion today is that much of the baroque architecture of the 
17th and 18th centuries is gaudy and flamboyant.