To the rest of India Dhana Jiru is just cumin and coriander seeds ground together. But to the Parsi community it is a very different beast.
"“Many people think that the dhana jiru is just dhaniya and jeera powder, but the Parsi dhana jiru is made up of around 15-20 different spices, including elaichi, star anise, tezpatta, chillies, pepper balls, cloves…you name it, it’s got it. Dhansak and dhana jiru are a little similar, the former has maybe 3 to 4 less ingredients. The Parsi sambar mix has a mix of spices such as mustard and methi, and they’re mixed in mustard oil, so it’s a slightly wettish-powder. Another one is the curry masala, which has around 4 to 5 ingredients, including white sesame seeds, jeera, and khus khus,” says Shelley."
#MyBombayKitchen uses 17 different spices for dhana jiru. I came here to say that, but found this article (that I quoted) which expresses it better.