Thank you for all of these great answers. I am just getting into wine, so I really had no clue.

They come from essentially the same grape, just different names for different growing regions.

Shiraz or Syrah is a variety of grape used in wine. The names are interchangeable. It is called Syrah in France and most often in the United States. In South Africa, Australia, and Canada it is most commonly known as Shiraz. In Australia it used to be called Hermitage up to the late 1980s. It should not be confused with Petite Sirah, a synonym for Durif, which is a different type of grape. It got its name from Shiraz--the city of flowers, wine and poetry in Persia/Iran--in the heart of an ancient winemaking region

nothing. in some regions, it's called syrah. in others, it's called shiraz

Yes, they are the same. Most Shiraz brands I see are from Australia but the grape combination for this wine is also found in Southern France and the U.S.