What are the differences in curry powders at the store?

yes. find an Asian grocer. they have lots of different curry powders

here are literally thousands of “curry powders”, each of which was uniquely suited for the produce and tastes of the region it developed in.

Indians tend to use garam masala (another type of curry powder, of which there are also many incantations) the way people in the west use curry powder. An exception is in the south they have developed a mixture called “sambhar powder” that is quite different from garam masala.

Actually, the word curry is derived from the south Indian word curriel, which was used in the local language (Tamil) for a fish stew that had tamarind and curry leaves (which is where these leaves also get their name even in local languages). This was then picked up and transformed into the present “curry” by the British. The word “curry”, in its English sense, has no direct translation into any to India’s fifteen languages, and Indians do not use the term even when speaking English.

ALSO:
Curry powder is actually a pulverized blend of up to 20 spices, herbs and seeds. Among those most commonly used are cardamom, chiles, cinnamon, cloves, coriander, cumin, fennel seed, fenugreek, mace, nutmeg, red and black pepper, poppy and sesame seeds, saffron, tamarind and turmeric (the latter is what gives curried dishes their characteristic yellow color). Commercial curry powder (which bears little resemblance to the freshly ground blends of southern India) comes in two basic styles — standard, and the hotter of the two, “Madras.” Since curry powder quickly loses its pungency, it should be stored, airtight, no longer than 2 months. For information on specific spices used in this blend, see individual