Basic information :
It is spelled S'mores not Smores. (Single being S'more. Not Smore. )
A s'more is a traditional campfire treat popular in the United States, consisting of a roasted marshmallow and a layer of chocolate sandwiched between two pieces of graham cracker.
Thank you Wikipedia!
S'more appears to be a contraction of the phrase, "some more".
While the origin of the dessert is unclear, the first recorded version of the recipe can be found in the publication "Tramping and Trailing with the Girl Scouts" of 1927. It is unknown whether the Girl Scouts were the first to make and enjoy s'mores, but there appears to be no earlier claim