Definition 1 of 1
If you order too many dry dishes, the waiter will grow increasingly concerned for your health and safety, and will gently suggest "gravy dish, saar". A gravy dish is considered essential to a meal, and unnamed, horrible things happen to diners attempting to eat rice or rotis with only dry dishes.
If you turn down the waiter's offer, his eyes will widen, he'll start shaking a little and there'll be tears in his eyes as he implores, "No saar, gravy dish is a must. Cancel one dry dish?" He'll gesture towards the ladice and children at the table as if to say, "How can you treat them so?"
If you're pushy enough to persist, he will bring you the dry dishes, and then triumphantly set down gratis bowls of "gravy". "To have with naan, saar."
Gravy dish is a must.