The term 'Leaf Opening' refers to the small openings in the leaves of plants. These openings, known as stomata (5 letters) and pores (4 letters), allow for the exchange of gases between the plant and the atmosphere. Stomata are typically found on the underside of the leaf and are surrounded by guard cells that regulate the opening and closing of the STOMA. Pores are found on the surface of the leaf and are used for the same purpose as stomata.