An alternative theory suggests that the word was imported to Balkans by Romani speakers, who carried it from Indic languages where aré and ré are used in a similar manner, functioning as an "interjection of calling, of astonishment, of contempt, of disrespect (as to an inferior), of anger, etc.".
Like "hey!" it can be used as an exclamation, often used to get attention or express surprise, and so it corresponds in some ways to exclamations such as "wow!".
In the general mood of the language, sometimes re by itself is considered rude, if not offensive (eg. "Stand up, re" > "You, stand up now!"). However if followed by sy ("you") or the addressee's name it is considered milder, and friendly (eg. "Stand up, re George" > "Stand up, my friend George"). Of course the above is not always standard since everything depends on the context and the voice intonation.
It is very common for Greeks raised in Greece but living abroad (especially in the UK) to use re semi-jokingly when speaking English in the same way they use it when they speak Greek (e.g. "Are you serious re?", "How are you re Jim?" ) Similarly, Greek rappers will use it along with the interjection man! as in "Re man".
In the Greek American community of Tarpon Springs, Florida, a variation of the word is used with the same meaning. Instead of the term Re, with the rolling of the "r", being said, the Greeks there instead say "Ray", with no rolling of the "r". "Ray" is thus said as "ray" would be said in typical English. "Ray, lets go to the Sponge Docks," or "What's up ray?" is how the term is used in Tarpon Springs. This is common only in Tarpon Springs, and the usage of the term by the Tarpon Greeks is often mocked by Greek Americans throughout the country.