The cross-Atlantic confusion is absolutely first class. Literally has brought tears to my eyes.
After living in the US for 8 years I've become fairly fluent in American, so here we go.
Curry powder does have chili powder in it. Chili peppers are the fuel for heat in Mexican, Thai and Indian cuisine. Curry powder is just a ground-up-to-powder mixture of herbs and spices (including chili, in varying degrees depending on temperature).
Chili is not minced meat with red beans - as served in England. That would be like saying curry is limited to minced meat and curry powder.
Real chili is as varied as real curries are. Mexican food is just as varied as Indian.
Peppers in the US refers to at least 3 things. Bell Peppers are what we British would call Peppers. Peppers are what the British would call Chili Peppers. Pepperchinis (sometimes called banana peppers) are the sort of pickled chilies you would see offered in your average Kebab establishment. They tend to have just enough heat to matter - but nothing a decent beer won't take care of.
Kebabs, by the way, (to those from the US) are not just the food-on-a-skewer variety you have at barbecues - the more common kind in the UK resemble what you call Gyros (a word which almost means social security check to the British) and are loaded with awesome extras like chili sauce and pepperchinis.
Finally we have jalapenos - a type of pepper that is universally hot, but varies in heat from medium to vindaloo. They are the business, and every decent plate of nachos is covered in these beauties. Get a seed caught in your throat or under your tongue and you'll definitely know about it. Don't put your fingers in your eyes after eating US nachos.
Hope that helps - probably not, probably just made things worse.