Coke, Pepsi and similar things were "sody" as in "sody pop". You bought six sodies, you had a glass of sody. If you were particular you specified: glass of vanilla Coke (again, nothing like what comes in cans), bottle of Pepsi, some Bubble-Up.

A "soda" was made at the soda fountain and included ice cream. "Soda" could also be carbonated water, as in "Scotch and soda" but such wussy drinks were unusual -- it was "I'll have a highball" and you got Seagram's Seven Crown or Four Roses with ice and Seven-Up.

A fountain Coke or Pepsi was made with a specified number of syrup squirts and then carbonated water.

"Tonic" was quinine water.