Chile or Chili, it's Still Green.

Is it Chile or Chili? If it's the country in South America, it's Chile. If it's the singer from the group "TLC", it's Chilli; and when it's very cold outside, well that's Chilly. However, when it's the vegetable, it's the Green Chile Pepper, but when exactly does it become Chili? Then there's the plural, is it Chiles or Chilies? Confusing isn't it; and so many sources have so many definitions