In english, it means "luck", "prosperity" or "salvation"

In English, we recognize it as a Nazi salute.

This isn't an English word. Where did you hear it, Davide?

"Heil" is not an English word. It is a German word. There is a corresponding English word, "Hail!" "Hail!" is almost obsolete. It is a greeting or an acclamation. Similar to "Ave" or "Salve," I think. "Hail, Caesar!" The official music used to announce the President of the United States is entitled "Hail to the Chief" (no words are sung). It's actually a poem by Sir Walter Scott and refers to Scottish clans! The English word "hail" can also mean grains of ice falling from the sky. During the Second World War, Germans were taught to greet each other with the phrase "Heil Hitler" and this has become a strong association for "Heil."

Thanks also to Peachey and SuKi (I'm not the best, they bring more than me in iTalki :) )