Percival P. Cassidy wrote:

The last of these is regional: in some parts of the USA they are all
"coke," in others all "soda," and in yet others all "pop."

Unless you're in Boston (bah-stun), in which case the generic word is
tonic (tah-nik). Don't ask me why. At least that's how it was 30 years
ago when I lived there.

Jerry