Chili is a fruit. It is used as a spice to add pungency or piquancy and flavor to dishes. In American English, the spelling is usually chili; in British English, chilli (with two ls) is used consistently.Chili is a fruit. It is used as a spice to add pungency or piquancy and flavor to dishes. In American English, the spelling is usually chili; in British English, chilli (with two ls) is used consistently.