संतरा comes from the name of the Portuguese town of Sintra. Greeks call oranges 'Πορτοκάλι' too. The Portuguese use the Arabic root (laranja). The Arabs brought the orange to Spain from the Far East: al-naranj > naranja > an orange. (16thC English called them noranges!) Interestingly the Sanskrit for Orange was narang (नारंग) too. The Germans simply call it 'Apfelsine' - Chinese Apple, although Orange is becoming more common. Does anyone else have any other interesting Orange stories?
Another thing - orange is also called Naarangi(नारंगी) in Hindi. Sounds quite related to the Arab Naranj.
In Malayalam, the original name was "Naarangai". The English-derived "orange" is more frequent nowadays.
I find this interesting, especially because I have been to Sintra. It is my favorite spot in Portugal.
How do you know for certain संतरा derives from Sintra, especially when the early Portuguese in India didn't use that word?
नारङ्ग (नाग the best + रङ्ग color) is a Sanskrit loanword in Arabic and other languages.
It is typically used when speaking in generalizations. Such as, "horses are big animals" - "घोड़े बड़े जानवर होते हैं"