The papaya is the fruit of the plant Carica papaya, in the genus Carica. It is native to the tropics of the Americas, and was cultivated in Mexico several centuries before the emergence of the Mesoamerican classic cultures. It is sometimes called a "big melon" or a "paw paw" but the North American pawpaw is a different species, in the genus Asimina.

It is a large tree-like plant, the single stem growing from 5 to 10 meters tall, with spirally arranged leaves confined to the top of the trunk; the lower trunk is conspicuously scarred where leaves and fruit were borne. The leaves are large, 50-70 cm diameter, deeply palmately lobed with 7 lobes. The tree is usually unbranched if unlopped. The flowers are similar in shape to the flowers of the Plumeria but are much smaller and wax like. They appear on the axils of the leaves, maturing into the large 15-45 cm long, 10-30 cm diameter fruit. The fruit is ripe when it feels soft (like a ripe avocado or a bit softer) and its skin has attained an amber to orange hue. The fruit's taste is vaguely similar to pineapple and peach, although much milder without the tartness.