Orange by any other name is sweet. The word 'Orange' came from Sanskrit (नारङ्ग nāraṅga) and originally from Dravidian, borrowed by Persian (nārang), Arab (nāranj) and the European. When the orange reached Europe via Portugal, they called it 'the Portugese One' (Portokal), forgetting the Sanskrit origin, Orange was called the 'Apple from China.' as in German Alfelsine. Don't forget the sweet sound of nāraṅga.
The Navel Orange has a protrusion at the apex, looking like a belly button hernia-actually a second fruit. If you strip the button, you will see a small fruit.