Guineos usually refers to a green (unripened) banana

Banana

Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....

. The term guineo is sometimes used in reference to its ripened counterpart: the yellow (ripened) banana

Banana

Banana is the common name for herbaceous plants of the genus Musa and for the fruit they produce. Bananas come in a variety of sizes and colors when ripe, including yellow, purple, and red....

. Some make a distinction between the two and refer to green bananas as guineos verdes (green bananas) and yellow bananas as guineos maduros (ripe bananas) or just maduros (ripe)

Guineos are not to be confused with plantain

Plantain

Plantain is the common name for herbaceous plants of the genus Musa. The fruit they produce is generally used for cooking, in contrast to the soft, sweet banana...

s, 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. In Dominican and Puerto Rican cooking, they are used (while green) in the following dishes:

• Pasteles
  Pasteles
  Pasteles are a traditional dish in several Latin American countries. In Puerto Rico, the Dominican Republic, Trinidad and Tobago, the Caribbean coast of Colombia, and Panama, it is similar to a tamale. In Central American cuisine, it more closely resembles a British pasty or an Italian calzone.In...
  
  
• Vianda
• Alcapurrias
• Guineos en Escabeche
  Escabeche
  Escabeche is a typical Mediterranean cuisine which refers to both a dish of poached or fried fish that is marinated in an acidic mixture before serving, and to the marinade itself...
  
  

Guineo this word comes from pre-roman times, it is considered an africanism