A naartjie (Citrus reticulata, Citrus nobilis), or nartjie, is a soft loose-skinned South African citrus fruit. It is also known as a mandarin, satsuma or tangerine outside of South Africa.
The name is Afrikaans and is originally from the Tamil word nartei meaning citrus. The word has been used in South Africa since 1790, but the first written recorded English use is by Graham Green in the Tavern of the Seas 1947.
References
Jean Branford: A dictionary of South African English. Oxford 1978.