While reading the book of Numbers (I am a Christian, I don't know if it is referred to something else in Judaism), I came across the passage (Numbers 12:1-15) where Miriam and Aaron were speaking against Moses for taking a Cushite wife. I wanted to know if the term Cushite or Cushi is used to refer people of African descent, or specifically Ethiopia, or if not what exactly it does/did refer to. Obviously google gives results all over the map, it would be nice to get some real facts.
See this comprehensive and well sourced paper on the topic by one of our site regulars. Cush was the son of Cham, and the grandson of Noah (Exodus 10:6), and according to the Midrash (Genesis Rabbah 36:7), he was cursed by his grandfather to be dark-skinned.
In terms of the location of the land of Cush, he writes:
The essay explores many possible interpretations of Moshe's wife being called a "Cushite". Many explain that she was not actually Ethiopian, but was described as a "Cushite" as an expression of her beauty (see Rashi to Numbers 12:1).
i find it interesting that people will quote sources from commentators thousands of years after the Tanakh, and historians later still, but no one points to a pretty clear Biblical reference on using Cushi to have it refer specifically to someone of a particular skin color:
Jeremiah 13:23 כג הֲיַהֲפֹךְ כּוּשִׁי עוֹרוֹ, וְנָמֵר חֲבַרְבֻּרֹתָיו; גַּם-אַתֶּם תּוּכְלוּ לְהֵיטִיב, לִמֻּדֵי הָרֵעַ. 23 Can the Cushite change his skin, or the leopard his spots? Then may ye also do good, that are accustomed to do evil.
So it is definitely fair to assume that Cushi can mean someone who is black (or dark) skinned. We can argue all day long where the geography of the Cushites were considered to be.