My classics teacher at NYU, 1969, told us that Hellas meant "the land". Thus, Hellenes would translate as people of the land. I also found this info in my college history textbook when I taught at Notre Dame College in Manchester, NH in 1993. These are two sources that seem to agree on this point. It makes sense to me that this could actually be a correct answer to the question.
Hellas is the proper name for Greece. Zito means hail. As in hail ceasar.
Hellene is Greek for Greek. In Greek their country is called Hellas.
It is not a nickname, but the Greeks call themselves Hellas after their legendary founder, Helen (a dude). Their nickname is actually Greek after being mistaken for the Graeci tribe by the Roman peeps.
The real name is Hellas ( Ellines) . But In the mid-second century. eg and when the Romans invaded Greece, the first point of disembarkation was Etoloakarnania somewhere (can not remember the name of the region), where a local resident Greek tribe called "Greki" (as we say Sarakatsani,Pomaks, Albanians, etc.) and hence Graecia.
Hellenistic is derived from the Greek's own, self described name "Hellens" so it just means Greek. It is mostly used to describe Ancient Greek History and Culture. They both allowed males to vote.
Hellas is the proper name for Greece. Zito means hail. As in hail ceasar.
George Hellas's birth name is George David Hellas III.
DeAgostini Hellas was created in 1995.
Hellas - poem - was created in 1822.
Fly Hellas was created in 2009.
Fly Hellas ended in 2011.
SC Hellas was created in 1974.
Hellas On-Line was created in 1993.
Fate of Hellas happened in 2008.
Hellas Jet ended in 2010.
Hellas Jet was created in 2002.
George Hellas is 5' 8".