chili pepper vs green pepper

chili pepper

noun
  • Any fruit of a plant of the botanical genus Capsicum, which has a spicy/burning flavour because it contains capsaicin. (Not all chili peppers are particularly spicy, but all true chili peppers contain some capsaicin, in contrast to e.g. the bell pepper, which is not a true chili pepper and does not.) 

green pepper

noun
  • The green, unripe, form of the sweet bell pepper. Popular in cooking, especially Italian cuisine. The unripe bell pepper is green and generally changes to other colors as it matures, cultivars exist for red, orange, yellow and other shades. 

  • A green variety of dried peppercorn, made from the unripe berries by treating them in a manner that retains the green colour. 

How often have the words chili pepper and green pepper occurred in a corpus of books? (source: Google Ngram Viewer )