Coffee bean is essentially the seed of a berry from a coffee plant. The bean comes in 2 halves. Peaberry is a coffee bean which is in whole bean and not in 2 halves. In every coffee plant, http://premier-pharmacy.com/product-category/hair-loss/ less than 5% of the berries are Peaberry.
Arabica coffee beans are have a more elongated oval shape. The split in between is more S-like.
Robusta coffee beans are a rounder oval in shape. The split tends to be straighter.