Here's a breakdown of the meaning:
* Kara: Means "black" in Turkic languages.
* Kum: Means "sand" in Turkic languages.
The desert's name likely originates from the dark color of the sand in some areas, particularly in the eastern part of the desert where it's rich in iron oxides. While not entirely black, the sand's darker hue contrasts with the lighter sands found in other parts of the desert.