Maclura pomifera, commonly known as the Osage orange ( OH-sayj), is a small deciduous tree or large shrub, native to the south-central United States. It typically grows about 8 to 15 metres (30–50 ft) tall. The distinctive fruit, a multiple fruit, is roughly spherical, bumpy, 8 to 15 centimetres (3–6 in) in diameter, and turns bright yellow-green in the fall. The fruits secrete a sticky white latex when cut or damaged. Despite the name "Osage orange", it is not related to the orange. It is a member of the mulberry family, Moraceae. Due to its latex secretions and woody pulp, the fruit is typically not eaten by humans and rarely by foraging animals. Ecologists Daniel H. Janzen and Paul S. Martin proposed in 1982 that the fruit of this species might be an example of what has come to be called an evolutionary anachronism—that is, a fruit coevolved with a large animal seed dispersal partner that is now extinct. Evidence and arguments pro and con their hypothesis followed for decades afterwards.

Maclura pomifera has many names, including mock orange, hedge apple, hedge, horse apple, crab apple, monkey ball, monkey brains and yellow-wood. The name bois d'arc (from French meaning "bow-wood") has also been corrupted into bodark and bodock.