The word curry is used across a dozen cuisines and means something different in each. Tracing how that happened explains a good deal about how Indian cooking travelled.
The term was an outsider's label
Indian languages have specific names for individual preparations and no general word covering all of them. A single umbrella term was applied from outside rather than adopted from within.
It appears to derive from a southern word for a cooked accompaniment eaten with rice, generalised by traders and administrators into a name for spiced dishes as a class.
That generalisation is why the word feels imprecise to anyone cooking the food, since it groups together preparations with no common technique.
Britain built a dish around the word
Returning colonial households wanted a reproducible version of what they had eaten, which produced pre-mixed curry powder and a standardised sauce.
That powder fixed a particular spice combination in place, and it became the reference point for a whole tradition of British cooking that had no equivalent in India.
Later restaurant menus built on the same foundation, which is why the curry house tradition reads as its own cuisine rather than as transplanted regional cooking.
Japan received it at a remove
Japanese curry arrived through British naval practice rather than directly from India, which is why it is thickened with a flour roux in the European manner.
It became a staple of institutional and home cooking, sweeter and milder than either of its ancestors and served with short-grain rice.
The dish has since developed its own conventions and is now clearly Japanese rather than a version of anything else.
The Caribbean route was migration, not trade
Indentured labour from India brought cooking directly to the Caribbean, so the dishes there descend from household cooking rather than from a colonial simplification.
Local ingredients reshaped them substantially, and the spice blends that developed lean heavily on ingredients available in the region.
The result stayed closer to its origins in technique while diverging considerably in ingredients, which is the reverse of what happened in Britain.
Why the word is contested now
Cooks and writers increasingly avoid the term because it flattens distinctions between preparations that share almost nothing beyond being spiced and served with a staple.
Others keep it as a practical label that diners understand, particularly on menus where precision would require explaining several regional traditions at once.
Both positions accept the same underlying point, which is that the word describes a category invented for convenience rather than one that existed in the cooking itself.