The Collaborative International Dictionary of English v.0.48:

Soda pop \So"da pop\, n.
   a popular non-alcoholic beverage, sweetened by various means,
   containing flavoring and supersaturated with carbon dioxide,
   so as to be effervescent when the container is opened; -- in
   different localities it is variously called also soda,
   pop, mineral water, and minerals. It has many variants.
   The sweetening agent may be natural, such as cane sugar or
   corn syrup, or artificial, such as saccharin or aspartame.
   The flavoring varies widely, popular variants being fruit
   juices, fruit sirups, cream, or cola flavoring; the soda pop
   is usually served chilled.

   Note: Several large corporations started primarily as
         bottlers of soda pop, such as Coca-Cola,
         Pepsi-Cola, and Dr. Pepper.
         [PJC]