No, but I can see why you'd think that from my statement. The concept is only semi-defined via the dictionary definition of god. However, not all parts of the definition apply to god xyz and so when arguing against a theist of xyz, an atheist would only only use the definitions that apply. But in the broader sense, an atheist disbelieves in
all the (supernatural) definitions. Metaphors, such as claiming a leader is a god amongst his people, obviously don't count.
http://dictionary.reference.com/browse/god?r=75
And I don't see why this would lead you to thin atheists are absolutists.