Etymology of Delhi

Today I came across a maxim in Sanskrit called Dehalideepa nyaya (देहलीदीप न्यायः) . Dehali (देहली) in Sanskrit is ‘threshold’. The nyaya literally means ‘The maxim of a lamp on threshold’. This nyaya is used to denote something which serves a two-fold purpose at the same time, just like a lamp placed on the threshold of house lights both inside the house and outside the house.
So, Dehali means a threshold. It was probably named ‘threshold’ as it served as gateway to invaders from the north. It was the primary entry point to mainland India. Gradually dehali became dilli and then rechristened to Delhi. ‘Dehali’ is still used in Kannada and it is nostalgic for me to recollect 90’s sign “Ideega Dehalige”(ಇದೀಗ ದೆಹಲಿಗೆ = Over to Delhi) on Doordarshan after Kannada news.