The Caucasus mountain region (modern day Georgia, Armenia, Azerbaijan), is where all Semetic and Indo-Aryan/Indo-European cultures theoretically originated.
This includes, Europeans, Iranians, Arabs (including North Africans), Hebrews, etc.
They are all Caucasian.
Hate to be the "well, actually" guy here, but this is some old-school anthropology here! If you do a quick wikipedia search, be sure read the
disclaimer on the first line that the idea of a "Caucasian race" is an outdated concept.
Yes, there is a place in Central Asia called the Caucasus. I've been there! Beautiful place. The "theory" that white people originated from here is because this is said to be where Noah's Ark landed after the great flood. White people in the 1700s, trying to develop categories of people, decided that there were 3 races. These "races" had nothing to do with ethnicity (language, culture, etc.) and were strictly based on physical appearances, or types. They also decided that Circassian women were the most beautiful in the world and that whites must therefore have descended from them.
Caucasian then, started out being "the race with narrow noses, straight jaws, flat faces, small teeth and narrow mouths," (skin color was not a factor). Eventually,
caucasian became a synonym for "white people," who then spent a lot of time trying to prove that they were the more highly evolved race and that those with darker skin were less evolved. To that end, they invented the theory of "sub-races" for all the people with darker skin.
Over the last 100 years, we've come to understand the human genome and the role that socialization plays into group identities. We don't guess at the relationships between people groups by looking at the outside, we analyze genes and trace ethnographies.
TL;DR: "Caucasian" is not really a useful/helpful/accurate category. The term is outdated, but is still in use today (mostly in America) to refer to fair-skinned people of European descent.