Green chile

Green chile describes a wide family of chile peppers, which are the unripe fruit of plants of the genus Capsicum. Most chiles contain capsaicin (8-methyl-N-vanillyl-6-nonenamide), a chemical that tricks the skin into thinking it has been burned or abraded by activating VR1, a receptor found in the skin and mucous membranes. 

Some common green chiles include the Anaheim, Cubanelle, Jalapeño, Serrano, New Mexico, and Hungarian Wax. They range heat from moderate (Anaheim, Cubanelle) to fairly spicy (Serrano). 

All green chiles have a fresh, green/grassy note in common that pair well with tomatillos, [ingredient=cilantro cilantro], and [ingredient=tomato tomatoes]. They are culinarily important in Mexican, Vietnamese, and Thai cuisines.