well, you can combine a colour (grau - grey) and a noun (Flasche - bottle) to one word in German, which then simply means grey bottle. Nevertheless the possibility of forming a grammatically correct word this way, does not mean the the word makes sense or is used in any way. Google results directed me to “graue Flasche” (two words), so it tries to give a synthetic word context and sense, while not really recognising it.
If you look for information on a German word, google is not the best place to search. If it is a good German word, you’d find it in the “Duden”:
www.duden.de which does not know it.