Guineos (pronounced ghee-neh-oss) usually refers to an unripened banana. The term guineo is sometimes used in reference to its ripened counterpart: the yellow (ripened) banana. Etymology of the word Guineo comes from Guinea, a country in the west of Africa, as it is one of the places from which bananas originate. Some make a distinction between the two and refer to green bananas as guineos verdes (green bananas) and yellow bananas as guineos (ripe bananas).
Guineos are not to be confused with plantains, which are far starchier than the guineo and cannot be used in the same ways.
Guineos are used widely in Latin American cooking as they are versatile, inexpensive, and filling.