Skaara translated Goa'uld by God in Children of the Gods.
So most likely the word Goa'uld is the Abydonian word for God.
However it never is mentioned again.
I am guessing that the word God was created from Goa'uld.
The Goa'uld played the roles of gods, but because the idea didn't exist in either Goa'uld nor Unas and Human cultures alike, they probably didn't have a word yet for it. And eventually, because of the Goa'ulds impersonifications, the name of their species became the word for the idea.
Then the languages evolved and a new word made out of Goa'uld was created to represent the idea. That word became God.
