green pepper vs red pepper

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. 

red pepper

noun
  • A red-colored, ripe, bell or sweet pepper. Unripe peppers of this variety are green and edible but not as sweet. 

  • Spicy pepper. 

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