An American person is from the United States of America, sure.
If someone said “I met this guy from America” I would genuinely wonder whether they wanted me to assume that the guy was from the USA or if they were about to clarify.
In English speaking countries, when you refer to anything from “The Americas”, there’s a likelihood it’s from the United States of America, and one might assume that, but it’s something less than “widely understood” abbreviation.
Uh, I’m not certain that’s true.
An American person is from the United States of America, sure.
If someone said “I met this guy from America” I would genuinely wonder whether they wanted me to assume that the guy was from the USA or if they were about to clarify.
In English speaking countries, when you refer to anything from “The Americas”, there’s a likelihood it’s from the United States of America, and one might assume that, but it’s something less than “widely understood” abbreviation.