In at least some parts of the
Southern U.S., any
soft drink, regardless of
actual brand. Typical exchange in a restaurant:
Server: And what would you like to drink?
Customer: I'll have a Coke.
Server: What kind?
Customer: Um, Sun Drop
In areas where this is customary, ordering a soft drink will
usually work; however, asking for a "pop" is likely to score
a puzzled look.