Coke (a cola)
Down here, in the South, a coke is any kind of soft drink as in, "do you want a coke? What kind? I've got Sprite, Pepsi.."
One of our college friend's first jobs was with Coca-Cola. We called him a "Coke Narc." Coca-Cola aggressively defends its trademark, and Jim traveled around the US going into restaurants and other businesses that sold soft drinks. He'd order a Coke then take a sample back to Coca-Cola to be tested to ensure that the business was actually serving Coke. It seems most businesses have gotten the message. Now when ever I order a Coke in a Pepsi shop, the waiter asks, "Is Pepsi OK?" And no, it isn't although I will drink some Pepsi products.
S