Originally Asian, we think of curry as being a spice when it is actually a blend of various spices. Turmeric gives its powerful yellow colour to the famous curry powder. Please note that curry leaves are not related: not so famous, they come from a citrusy tree.
They both come from India, are visually very similar, but the traditional Indian curry contains chili pepper, making it a perfect combination to coconut milk, when Madras curry is a sweet curry that adds fragrance to dishes.
In Thailand, curry is usually a coconut-based paste. There are many versions, the most popular being the green curry paste made of chili pepper, garlic, ginger and combava. Red and yellow curry pastes are sweeter.
Japanese katsus designate any dish made of battered and fried meat. Traditionally served with a curry sauce, it is usually very fragrant and even sometimes contain fruits like dates.